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<refentry id="nping-man">
<refmeta>
<refentrytitle>nping</refentrytitle>
<manvolnum>1</manvolnum>
<refmiscinfo class="source">Nping</refmiscinfo>
<refmiscinfo class="manual">Nping Reference Guide</refmiscinfo>
</refmeta>
<refnamediv id="nping-man-name">
<refname>nping</refname>
<refpurpose>Network packet generation tool / ping utility</refpurpose>
</refnamediv>
<!-- body begins here -->
<refsynopsisdiv id="nping-man-synopsis">
<cmdsynopsis sepchar=" ">
<command>nping</command>
<arg choice="opt" rep="norepeat">
<replaceable>Options</replaceable>
</arg>
<arg choice="req" rep="norepeat">
<replaceable>targets</replaceable>
</arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1 id="nping-man-description">
<title>Description</title>
<indexterm><primary>Nping</primary><secondary>description of</secondary></indexterm>
<web>
<note><para>This document describes the very latest version of
Nping available from <ulink url="https://nmap.org/nping"/> Please
ensure you are using the latest version before reporting that a
feature doesn't work as described.</para></note>
</web>
<para>Nping is an open-source tool for network packet generation,
response analysis and response time measurement. Nping allows
users to generate network packets of a wide range of protocols,
letting them tune virtually any field of the protocol
headers. While Nping can be used as a simple ping utility to
detect active hosts, it can also be used as a raw packet generator
for network stack stress tests, ARP poisoning, Denial of Service
attacks, route tracing, and other purposes.</para>
<para>Additionally, Nping offers a special mode of operation called
the "Echo Mode", that lets users see how the generated probes change
in transit, revealing the differences between the transmitted packets and
the packets received at the other end. See section "Echo Mode" for details.
</para>
<para>The output from Nping is a list of the packets that are being sent
and received. The level of detail depends on the options used.</para>
<!--
<para>Additionally, Nping can provide further information on targets,
including reverse DNS names and MAC addresses.</para>
-->
<para>A typical Nping execution is shown in <xref linkend="nping-man-ex-repping" xrefstyle="select: label nopage"/>. The only Nping arguments used in
this example are <option>-c</option>, to specify the number of times to
target each host, <option>--tcp</option> to specify TCP Probe Mode,
<option>-p 80,433</option> to specify the target ports; and then the two
target hostnames.</para>
<example id="nping-man-ex-repping"><title>A representative Nping execution</title>
<indexterm><primary><option>-c</option> (Nping option)</primary><secondary>example of</secondary></indexterm>
<indexterm><primary><option>--tcp</option> (Nping option)</primary><secondary>example of</secondary></indexterm>
<indexterm><primary><option>-p</option> (Nping option)</primary><secondary>example of</secondary></indexterm>
<screen format="linespecific">
# <userinput>nping -c 1 --tcp -p 80,433 scanme.nmap.org google.com</userinput>
Starting Nping ( https://nmap.org/nping )
SENT (0.0120s) TCP 96.16.226.135:50091 &gt; 64.13.134.52:80 S ttl=64 id=52072 iple<continuation/>n=40 seq=1077657388 win=1480
RCVD (0.1810s) TCP 64.13.134.52:80 &gt; 96.16.226.135:50091 SA ttl=53 id=0 iplen=4<continuation/>4 seq=4158134847 win=5840 &lt;mss 1460&gt;
SENT (1.0140s) TCP 96.16.226.135:50091 &gt; 74.125.45.100:80 S ttl=64 id=13932 ipl<continuation/>en=40 seq=1077657388 win=1480
RCVD (1.1370s) TCP 74.125.45.100:80 &gt; 96.16.226.135:50091 SA ttl=52 id=52913 ip<continuation/>len=44 seq=2650443864 win=5720 &lt;mss 1430&gt;
SENT (2.0140s) TCP 96.16.226.135:50091 &gt; 64.13.134.52:433 S ttl=64 id=8373 iple<continuation/>n=40 seq=1077657388 win=1480
SENT (3.0140s) TCP 96.16.226.135:50091 &gt; 74.125.45.100:433 S ttl=64 id=23624 ip<continuation/>len=40 seq=1077657388 win=1480
Statistics for host scanme.nmap.org (64.13.134.52):
| Probes Sent: 2 | Rcvd: 1 | Lost: 1 (50.00%)
|_ Max rtt: 169.720ms | Min rtt: 169.720ms | Avg rtt: 169.720ms
Statistics for host google.com (74.125.45.100):
| Probes Sent: 2 | Rcvd: 1 | Lost: 1 (50.00%)
|_ Max rtt: 122.686ms | Min rtt: 122.686ms | Avg rtt: 122.686ms
Raw packets sent: 4 (160B) | Rcvd: 2 (92B) | Lost: 2 (50.00%)
Tx time: 3.00296s | Tx bytes/s: 53.28 | Tx pkts/s: 1.33
Rx time: 3.00296s | Rx bytes/s: 30.64 | Rx pkts/s: 0.67
Nping done: 2 IP addresses pinged in 4.01 seconds
</screen>
</example>
<!-- This para is a bit jumbled together for man page rendering reasons -->
<!--
<para>The newest version of Nping can be obtained from
<ulink url="https://nmap.org"/>. The newest version of this man page
is available at <ulink url="https://nmap.org/book/nping_man.html"/>.
<notbook>It is also included as a chapter of <web><ulink url="https://nmap.org/book/"><citetitle>Nmap Network Scanning: The Official Nmap Project Guide to Network Discovery and Security Scanning</citetitle></ulink>.</web><notweb><citetitle>Nmap Network Scanning: The Official Nmap Project Guide to Network Discovery and Security Scanning</citetitle> (see <ulink url="https://nmap.org/book/"/>).</notweb></notbook>
</para>
-->
</refsect1>
<refsect1 id="nping-man-briefoptions">
<title>Options Summary</title>
<para>This options summary is printed when Nping is run
with no arguments. It helps people remember the most common options,
but is no substitute for the in-depth documentation in the rest of this manual.
Some obscure options aren't even included here.</para>
<!-- sortas="#" puts it before the entries that start with '-' in the options
section. -->
<indexterm class="startofrange" id="nping-usage-indexterm"><primary sortas="#">summary of options (Nping)</primary></indexterm>
<indexterm class="startofrange" id="nping-usage-nping-indexterm"><primary>command-line options</primary><secondary>of Nping</secondary></indexterm>
&nping-usage;
<indexterm class="endofrange" startref="nping-usage-nping-indexterm"/>
<indexterm class="endofrange" startref="nping-usage-indexterm"/>
</refsect1>
<refsect1 id="nping-man-target-specification">
<title>Target Specification</title>
<indexterm><primary>target specification</primary><secondary>in Nping</secondary></indexterm>
<para>Everything on the Nping command line that isn't an option or an
option argument is treated as a target host specification. Nping
uses the same syntax for target specifications that Nmap does. The
simplest case is a single target given by IP address or hostname.
</para>
<para>Nping supports
CIDR-style<indexterm><primary>CIDR (Classless Inter-Domain Routing)</primary></indexterm>
addressing. You can append <literal>/<replaceable>numbits</replaceable></literal> to an
IPv4 address or hostname and Nping will send probes to every IP
address for which the first <replaceable>numbits</replaceable> are the same as for the
reference IP or hostname given. For example, <literal>192.168.10.0/24</literal> would
send probes to the 256 hosts between 192.168.10.0
(binary: <literal>11000000 10101000 00001010 00000000</literal>)
and 192.168.10.255
(binary: <literal>11000000 10101000 00001010 11111111</literal>),
inclusive. <literal>192.168.10.40/24</literal> would ping exactly the same targets.
Given that the host scanme.nmap.org<indexterm><primary>scanme.nmap.org</primary></indexterm>
is at the IP address 64.13.134.52, the specification
<literal>scanme.nmap.org/16</literal> would send probes to the 65,536 IP addresses
between 64.13.0.0 and 64.13.255.255. The smallest allowed value is
<literal>/0</literal>, which targets the whole Internet. The largest value is <literal>/32</literal>,
which targets just the named host or IP address because all address
bits are fixed.
</para>
<indexterm><primary>address ranges</primary></indexterm>
<para>CIDR notation is short but not always flexible enough. For example,
you might want to send probes to 192.168.0.0/16 but skip any IPs
ending with .0 or .255 because they may be used as subnet network
and broadcast addresses. Nping supports this through octet range
addressing. Rather than specify a normal IP address, you can specify
a comma-separated list of numbers or ranges for each octet. For
example, <literal>192.168.0-255.1-254</literal> will skip all addresses in the range
that end in .0 or .255, and <literal>192.168.3-5,7.1</literal> will target the four
addresses 192.168.3.1, 192.168.4.1, 192.168.5.1, and 192.168.7.1.
Either side of a range may be omitted; the default values are 0 on
the left and 255 on the right. Using
<literal>-</literal> by itself is the same as <literal>0-255</literal>,
but remember to use <literal>0-</literal> in the first octet so the target
specification doesn't look like a command-line option. Ranges need
not be limited to the final octets: the specifier <literal>0-.-.13.37</literal> will send probes
to all IP addresses on the Internet ending in .13.37. This sort of
broad sampling can be useful for Internet surveys and research.
</para>
<para>IPv6 addresses can only be specified by their fully qualified IPv6
address or hostname. CIDR and octet ranges aren't supported for
IPv6 because they are rarely useful.</para>
<para>Nping accepts multiple host specifications on the command line,
and they don't need to be the same type. The command
<command>nping scanme.nmap.org
192.168.0.0/8 10.0.0,1,3-7.-</command> does what you would expect.
</para>
</refsect1>
<refsect1 id="nping-man-option-specification">
<title>Option Specification</title>
<para>
Nping is designed to be very flexible and fit a wide variety of needs.
As with most command-line tools, its behavior can be adjusted using
command-line options. These general principles apply to option
arguments, unless stated otherwise.
</para>
<para>
Options that take integer numbers can accept values specified in
decimal, octal or hexadecimal base. When a number starts with <literal>0x</literal>,
it will be treated as hexadecimal; when it simply starts with <literal>0</literal>, it
will be treated as octal. Otherwise, Nping will assume the number has
been specified in base 10. Virtually all numbers that can be supplied
from the command line are unsigned so, as a general rule, the minimum
value is zero. Users may also specify the word <literal>random</literal> or <literal>rand</literal> to
make Nping generate a random value within the expected range.
</para>
<para>
IP addresses may be given as IPv4 addresses (e.g.
<literal>192.168.1.1</literal>), IPv6 addresses (e.g.
<literal>2001:db8:85a3::8e4c:760:7146</literal>), or hostnames, which
will be resolved using the default DNS server configured in the host
system.
</para>
<para>
Options that take MAC addresses accept the usual colon-separated 6 hex
byte format (e.g. <literal>00:50:56:d4:01:98</literal>). Hyphens may also be used instead
of colons (e.g. <literal>00-50-56-c0-00-08</literal>). The special
word <literal>random</literal> or <literal>rand</literal> sets a random
address and the word <literal>broadcast</literal>
or <literal>bcast</literal> sets ff:ff:ff:ff:ff:ff.
</para>
</refsect1>
<refsect1 id="nping-man-general-operation">
<title>General Operation</title>
<indexterm><primary>general operation</primary></indexterm>
<para>Unlike other ping and packet generation tools, Nping supports
multiple target host and port specifications. While
this provides great flexibility, it is not obvious how Nping handles
situations where there is more than one host and/or more than one
port to send probes to. This section explains how Nping behaves in
these cases.
</para>
<para>
When multiple target hosts are specified, Nping rotates among them
in round-robin fashion. This gives slow hosts more time to send
their responses before another probe is sent to them. Ports are
also scheduled using round robin. So, unless only one port is
specified, Nping never sends two probes to the same target host and
port consecutively.
</para>
<para>
The loop around targets is the <quote>inner loop</quote> and the
loop around ports is the <quote>outer loop</quote>. All targets
will be sent a probe for a given port before moving on to the next
port. Between probes, Nping waits a configurable amount of time
called the <quote>inter-probe delay</quote>, which is controlled by
the <option>--delay</option> option. These examples show how it
works.
</para>
<variablelist>
<varlistentry>
<term>
<para>One target, three ports, and two rounds.</para>
</term>
<listitem>
<screen>
# <userinput>nping --tcp -c 2 1.1.1.1 -p 100-102</userinput>
Starting Nping ( https://nmap.org/nping )
SENT (0.0210s) TCP 192.168.1.77 &gt; 1.1.1.1:100
SENT (1.0230s) TCP 192.168.1.77 &gt; 1.1.1.1:101
SENT (2.0250s) TCP 192.168.1.77 &gt; 1.1.1.1:102
SENT (3.0280s) TCP 192.168.1.77 &gt; 1.1.1.1:100
SENT (4.0300s) TCP 192.168.1.77 &gt; 1.1.1.1:101
SENT (5.0320s) TCP 192.168.1.77 &gt; 1.1.1.1:102
</screen>
</listitem>
</varlistentry>
<varlistentry>
<term>
<para>Three targets, one port, and two rounds.</para>
</term>
<listitem>
<screen>
# <userinput>nping --tcp -c 2 1.1.1.1 2.2.2.2 3.3.3.3 -p 8080</userinput>
Starting Nping ( https://nmap.org/nping )
SENT (0.0230s) TCP 192.168.0.21 &gt; 1.1.1.1:8080
SENT (1.0240s) TCP 192.168.0.21 &gt; 2.2.2.2:8080
SENT (2.0260s) TCP 192.168.0.21 &gt; 3.3.3.3:8080
SENT (3.0270s) TCP 192.168.0.21 &gt; 1.1.1.1:8080
SENT (4.0290s) TCP 192.168.0.21 &gt; 2.2.2.2:8080
SENT (5.0310s) TCP 192.168.0.21 &gt; 3.3.3.3:8080
</screen>
</listitem>
</varlistentry>
<varlistentry>
<term>
<para>Three hosts, three ports, one round, inter-probe delay of 500&nbsp;ms.</para>
</term>
<listitem>
<screen>
# <userinput>nping --tcp -c 1 --delay 500ms 1.1.1.1 2.2.2.2 3.3.3.3 -p 137-139</userinput>
Starting Nping ( https://nmap.org/nping )
SENT (0.0230s) TCP 192.168.0.21 &gt; 1.1.1.1:137
SENT (0.5250s) TCP 192.168.0.21 &gt; 2.2.2.2:137
SENT (1.0250s) TCP 192.168.0.21 &gt; 3.3.3.3:137
SENT (1.5280s) TCP 192.168.0.21 &gt; 1.1.1.1:138
SENT (2.0280s) TCP 192.168.0.21 &gt; 2.2.2.2:138
SENT (2.5310s) TCP 192.168.0.21 &gt; 3.3.3.3:138
SENT (3.0300s) TCP 192.168.0.21 &gt; 1.1.1.1:139
SENT (3.5330s) TCP 192.168.0.21 &gt; 2.2.2.2:139
SENT (4.0330s) TCP 192.168.0.21 &gt; 3.3.3.3:139
</screen>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id="nping-man-probe-modes">
<title>Probe Modes</title>
<indexterm class="startofrange" id="nping-man-probe-modes-indexterm"><primary>probe modes</primary></indexterm>
<para>Nping supports a wide variety of protocols. Although in some cases
Nping can automatically determine the mode from the options used, it
is generally a good idea to specify it explicitly.
</para>
<variablelist>
<varlistentry>
<term>
<option>--tcp-connect</option> (TCP Connect mode)
<indexterm><primary><option>--tcp-connect</option> (Nping option)</primary></indexterm>
<indexterm><primary>TCP connect</primary><secondary>in Nping</secondary></indexterm>
<indexterm><primary>TCP connect</primary><seealso>connect scan</seealso></indexterm>
</term>
<listitem>
<para>TCP connect mode is the default mode when a user does not have
raw packet privileges. Instead of writing raw packets as most
other modes do, Nping asks the underlying operating system to
establish a connection with the target machine and port by
issuing the <literal>connect</literal> system call. This is the same high-level
system call that web browsers, P2P clients, and most other
network-enabled applications use to establish a connection.
It is part of a programming interface known as the Berkeley
Sockets API. Rather than read raw packet responses off the wire,
Nping uses this API to obtain status information on each
connection attempt. For this reason, you will not be able to
see the contents of the packets that are sent or received but
only status information about the TCP connection establishment
taking place.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--tcp</option> (TCP mode)
<indexterm><primary><option>--tcp</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>TCP is the mode that lets users create and send any kind of TCP
packet. TCP packets are sent embedded in IP packets that
can also be tuned. This mode can be used for many different
purposes. For example you could try to discover open ports by
sending TCP SYN messages without completing the three-way
handshake. This technique is often referred to as half-open
scanning, because you don't open a full TCP connection.
You send a SYN packet, as if you are going to open a real
connection and then wait for a response. A SYN/ACK indicates
the port is open, while a RST indicates it's closed. If no
response is received one could assume that some intermediate
network device is filtering the responses. Another use could be
to see how a remote TCP/IP stack behaves when it receives a
non-RFC-compliant packet, like one with both SYN and
RST flags set. One could also do some evil by creating custom
RST packets using an spoofed IP address with the intent of
closing an active TCP connection.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--udp</option> (UDP mode)
<indexterm><primary><option>--udp</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>UDP mode can have two different behaviours. Under normal
circumstances, it lets users create custom IP/UDP packets.
However, if Nping is run by a user without raw packet privileges
and no changes to the default protocol headers are requested,
then Nping enters the unprivileged UDP mode which basically sends
UDP packets to the specified target hosts and ports using the
<literal>sendto</literal> system call. Note that in this unprivileged mode it is
not possible to see low-level header information of the packets
on the wire but only status information about the amount of bytes
that are being transmitted and received. UDP mode can be used to
interact with any UDP-based server. Examples are DNS servers,
streaming servers, online gaming servers, and
port knocking/single-packet<indexterm><primary>port knocking</primary></indexterm>
authorization daemons.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--icmp</option> (ICMP mode)
<indexterm><primary><option>--icmp</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>ICMP mode is the default mode when the user runs Nping with
raw packet privileges. Any kind of ICMP message can be created.
The default ICMP type is Echo, i.e., ping. ICMP mode can be used
for many different purposes, from a simple request for a
timestamp or a netmask to the transmission of fake destination
unreachable messages, custom redirects, and router
advertisements.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--arp</option> (ARP/RARP mode)
<indexterm><primary><option>--arp</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>ARP lets you create and send a few different ARP-related packets.
These include ARP, RARP, DRARP, and InARP requests and replies.
This mode can ban be used to perform low-level host discovery,
and conduct ARP-cache poisoning attacks.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--traceroute</option> (Traceroute mode)
<indexterm><primary><option>--tcp-connect</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>Traceroute is not a mode by itself but a complement to
TCP, UDP, and ICMP modes. When this option is specified Nping
will set the IP TTL value of the first probe to 1. When the
next router receives the packet it will drop it due to
the expiration of the TTL and it will generate an ICMP
destination unreachable message. The next probe will have a TTL
of 2 so now the first router will forward the packet while the
second router will be the one that drops the packet and
generates the ICMP message. The third probe will have a TTL value
of 3 and so on. By examining the source addresses of all
those ICMP Destination Unreachable messages it is possible to
determine the path that the probes take until they reach their
final destination.
</para>
</listitem>
</varlistentry>
</variablelist>
<indexterm class="endofrange" startref="nping-man-probe-modes-indexterm"/>
</refsect1>
<!-- TCP CONNECT MODE ****************************************************** -->
<refsect1 id="nping-man-tcp-connect-mode">
<title>TCP Connect Mode</title>
<variablelist>
<varlistentry>
<term>
<option>-p <replaceable>port_spec</replaceable></option>,
<option>--dest-port <replaceable>port_spec</replaceable></option> (Target ports)
<indexterm significance="preferred"><primary><option>--dest-port</option> (Nping option)</primary></indexterm>
<indexterm significance="preferred"><primary><option>-p</option> (Nping option)</primary><see><option>--dest-port</option></see></indexterm>
</term>
<listitem>
<para>
This option specifies which ports you want to try to connect to.
It can be a single port, a comma-separated list of
ports (e.g. <literal>80,443,8080</literal>), a range
(e.g. <literal>1-1023</literal>), and any combination
of those (e.g. <literal>21-25,80,443,1024-2048</literal>).
The beginning and/or end values
of a range may be omitted, causing Nping to use 1 and 65535,
respectively. So you can specify <literal>-p-</literal> to target ports from 1 through
65535. Using port zero is allowed if you specify it explicitly.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-g <replaceable>portnumber</replaceable></option>,
<option>--source-port <replaceable>portnumber</replaceable></option> (Spoof source port)
<indexterm significance="preferred"><primary><option>--source-port</option> (Nping option)</primary></indexterm>
<indexterm significance="preferred"><primary><option>-g</option> (Nping option)</primary><see><option>--source-port</option></see></indexterm>
</term>
<listitem>
<para>
This option asks Nping to use the specified port as source port for
the TCP connections. Note that this might not work on all systems or
may require root privileges. Specified value must be an integer in
the range [0&ndash;65535].
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<!-- TCP MODE ************************************************************** -->
<refsect1 id="nping-man-tcp-mode">
<title>TCP Mode</title>
<variablelist>
<varlistentry>
<term>
<option>-p <replaceable>port_spec</replaceable></option>,
<option>--dest-port <replaceable>port_spec</replaceable></option> (Target ports)
</term>
<listitem>
<para>
This option specifies which destination ports you want to send
probes to. It can be a single port, a comma-separated list of
ports (e.g. <literal>80,443,8080</literal>), a range
(e.g. <literal>1-1023</literal>), and any combination
of those (e.g. <literal>21-25,80,443,1024-2048</literal>).
The beginning and/or end values
of a range may be omitted, causing Nping to use 1 and 65535,
respectively. So you can specify <literal>-p-</literal> to target ports from 1 through
65535. Using port zero is allowed if you specify it explicitly.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-g <replaceable>portnumber</replaceable></option>,
<option>--source-port <replaceable>portnumber</replaceable></option> (Spoof source port)
</term>
<listitem>
<para>
This option asks Nping to use the specified port as source port for
the TCP connections. Note that this might not work on all systems or
may require root privileges. Specified value must be an integer in
the range [0&ndash;65535].
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--seq <replaceable>seqnumber</replaceable></option> (Sequence Number)
<indexterm significance="preferred"><primary><option>--seq</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
Specifies the TCP sequence number. In SYN packets this is the initial
sequence number (ISN). In a normal transmission this corresponds to
the sequence number of the first byte of data in the segment.
<replaceable>seqnumber</replaceable> must be a number in the range
[0&ndash;4294967295].
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--flags <replaceable>flags</replaceable></option> (TCP Flags)
<indexterm significance="preferred"><primary><option>--flags</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option specifies which flags should be set in the TCP packet.
<replaceable>flags</replaceable> may be specified in three different
ways:
</para>
<orderedlist spacing="compact">
<listitem>
<para>As a comma-separated list of flags, e.g. <option>--flags syn,ack,rst</option></para>
</listitem>
<listitem>
<para>As a list of one-character flag initials, e.g. <option>--flags SAR</option> tells Nping to set flags SYN, ACK, and RST.</para>
</listitem>
<listitem>
<para>As an 8-bit hexadecimal number, where the supplied number
is the exact value that will be placed in the flags field of the
TCP header. The number should start with the prefix
<literal>0x</literal> and should be in the range
[0x00&ndash;0xFF], e.g. <literal>--flags 0x20</literal> sets the
URG flag as 0x20 corresponds to binary 00100000 and the URG flag
is represented by the third bit.</para>
</listitem>
</orderedlist>
<para>
There are 8 possible flags to set:
<literal>CWR</literal>,
<literal>ECN</literal>,
<literal>URG</literal>,
<literal>ACK</literal>,
<literal>PSH</literal>,
<literal>RST</literal>,
<literal>SYN</literal>, and
<literal>FIN</literal>.
The special value <literal>ALL</literal> means to set all flags.
<literal>NONE</literal> means to set no flags. It is important that
if you don't want any flag to be set, you request it explicitly
because in some cases the SYN flag may be set by default. Here is a
brief description of the meaning of each flag:
</para>
<variablelist>
<varlistentry>
<term>
CWR (Congestion Window Reduced)
<indexterm><primary>CWR (TCP flag)</primary></indexterm>
</term>
<listitem>
<para>
Set by an ECN-Capable sender
when it reduces its congestion window (due to a retransmit
timeout, a fast retransmit or in response to an ECN
notification.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
ECN (Explicit Congestion Notification)
<indexterm><primary>ECN (TCP flag)</primary></indexterm>
</term>
<listitem>
<para>
During the three-way
handshake it indicates that sender is capable of performing
explicit congestion notification. Normally it means that a
packet with the IP Congestion Experienced flag set was received
during normal transmission. See
RFC 3168<indexterm><primary>RFC 3168</primary></indexterm>
for more information.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
URG (Urgent)
<indexterm><primary>URG (TCP flag)</primary></indexterm>
</term>
<listitem>
<para>
Segment is urgent and the urgent pointer field
carries valid information.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
ACK (Acknowledgement)
<indexterm><primary>ACK (TCP flag)</primary></indexterm>
</term>
<listitem>
<para>
The segment carries an acknowledgement
and the value of the acknowledgement number field is valid and
contains the next sequence number that is expected from the
receiver.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
PSH (Push)
<indexterm><primary>PSH (TCP flag)</primary></indexterm>
</term>
<listitem>
<para>
The data in this segment should be immediately
pushed to the application layer on arrival.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
RST (Reset)
<indexterm><primary>RST (TCP flag)</primary></indexterm>
</term>
<listitem>
<para>
There was some problem and the sender wants to
abort the connection.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
SYN (Synchronize)
<indexterm><primary>SYN (TCP flag)</primary></indexterm>
</term>
<listitem>
<para>
The segment is a request to synchronize
sequence numbers and establish a connection. The sequence
number field contains the sender's initial sequence
number.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
FIN (Finish)
<indexterm><primary>FIN (TCP flag)</primary></indexterm>
</term>
<listitem>
<para>
The sender wants to close the connection.
</para>
</listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--win <replaceable>size</replaceable></option> (Window Size)
<indexterm significance="preferred"><primary><option>--win</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
Specifies the TCP window size, this is, the number of octets the
sender of the segment is willing to accept from the receiver at one
time. This is usually the size of the reception buffer that the OS
allocates for a given connection. <replaceable>size</replaceable>
must be a number in the range [0&ndash;65535].
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--badsum</option> (Invalid Checksum)
<indexterm significance="preferred"><primary><option>--badsum</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
Asks Nping to use an invalid TCP checksum for the packets sent to
target hosts. Since virtually all host IP stacks properly drop these
packets, any responses received are likely coming from a firewall or
an IDS that didn't bother to verify the checksum. For more
details on this technique, see
<ulink url="https://nmap.org/p60-12.html"/>.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<!-- UDP MODE ************************************************************** -->
<refsect1 id="nping-man-udp-mode">
<title>UDP Mode</title>
<variablelist>
<varlistentry>
<term>
<option>-p <replaceable>port_spec</replaceable></option>,
<option>--dest-port <replaceable>port_spec</replaceable></option> (Target ports)
<indexterm significance="preferred"><primary><option>--dest-port</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option specifies which ports you want UDP datagrams to be sent to.
It can be a single port, a comma-separated list of
ports (e.g. <literal>80,443,8080</literal>), a range
(e.g. <literal>1-1023</literal>), and any combination
of those (e.g. <literal>21-25,80,443,1024-2048</literal>).
The beginning and/or end values
of a range may be omitted, causing Nping to use 1 and 65535,
respectively. So you can specify <literal>-p-</literal> to target ports from 1 through
65535. Using port zero is allowed if you specify it explicitly.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-g <replaceable>portnumber</replaceable></option>,
<option>--source-port <replaceable>portnumber</replaceable></option> (Spoof source port)
<indexterm significance="preferred"><primary><option>--source-port</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option asks Nping to use the specified port as source port for
the transmitted datagrams. Note that this might not work on all systems or
may require root privileges. Specified value must be an integer in
the range [0&ndash;65535].
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--badsum</option> (Invalid Checksum)
</term>
<listitem>
<para>
Asks Nping to use an invalid UDP checksum for the packets sent to
target hosts. Since virtually all host IP stacks properly drop these
packets, any responses received are likely coming from a firewall or
an IDS that didn't bother to verify the checksum. For more
details on this technique, see
<ulink url="https://nmap.org/p60-12.html"/>.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<!-- ICMP MODE ************************************************************* -->
<refsect1 id="nping-man-icmp-mode">
<title>ICMP Mode</title>
<variablelist>
<varlistentry>
<term>
<option>--icmp-type <replaceable>type</replaceable></option> (ICMP type)
<indexterm significance="preferred"><primary><option>--icmp-type</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option specifies which type of ICMP messages should be
generated. <replaceable>type</replaceable> can be supplied in
two different ways. You can use the
<ulink url="http://www.iana.org/assignments/icmp-parameters">official type numbers assigned by IANA</ulink>
(e.g. <option>--icmp-type 8</option> for ICMP Echo Request), or you
can use any of the mnemonics listed in
<xref linkend="nping-man-icmp-types"/>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--icmp-code <replaceable>code</replaceable></option> (ICMP code)
<indexterm significance="preferred"><primary><option>--icmp-code</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option specifies which ICMP code should be included in
the generated ICMP messages. <replaceable>code</replaceable> can be
supplied in two different ways. You can use the
<ulink url="http://www.iana.org/assignments/icmp-parameters">official code numbers assigned by IANA</ulink>
(e.g. <option>--icmp-code 1</option> for Fragment Reassembly Time
Exceeded), or you can use any of the mnemonics listed in
<xref linkend="nping-man-icmp-codes"/>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--icmp-id <replaceable>id</replaceable></option> (ICMP identifier)
<indexterm significance="preferred"><primary><option>--icmp-id</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option specifies the value of the identifier used in some of
the ICMP messages. In general it is used to match request and
reply messages. <replaceable>id</replaceable> must be a number in
the range [0&ndash;65535].
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--icmp-seq <replaceable>seq</replaceable></option> (ICMP sequence)
<indexterm significance="preferred"><primary><option>--icmp-seq</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option specifies the value of the sequence number field used
in some ICMP messages. In general it is used to match request and
reply messages. <replaceable>id</replaceable> must be a number in
the range [0&ndash;65535].
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--icmp-redirect-addr <replaceable>addr</replaceable></option> (ICMP Redirect address)
<indexterm significance="preferred"><primary><option>--icmp-redirect-addr</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option sets the address field in ICMP Redirect messages. In
other words, it sets the IP address of the router that should be
used when sending IP datagrams to the original destination.
<replaceable>addr</replaceable> can be either an IPv4 address
or a hostname.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--icmp-param-pointer <replaceable>pointer</replaceable></option> (ICMP Parameter Problem pointer)
<indexterm significance="preferred"><primary><option>--icmp-param-pointer</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option specifies the pointer that indicates the location of
the problem in ICMP Parameter Problem messages. <replaceable>pointer</replaceable>
should be a number in the range [0&ndash;255]. Normally this option is
only used when ICMP code is set to 0 ("Pointer indicates the error").
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--icmp-advert-lifetime <replaceable>ttl</replaceable></option> (ICMP Router Advertisement Lifetime)
<indexterm significance="preferred"><primary><option>--icmp-advert-lifetime</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option specifies the router advertisement lifetime, this is,
the number of seconds the information carried in an ICMP Router
Advertisement can be considered valid for. <replaceable>ttl</replaceable>
must be a positive integer in the range [0&ndash;65535].
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--icmp-advert-entry <replaceable>addr</replaceable>,<replaceable>pref</replaceable></option> (ICMP Router Advertisement Entry)
<indexterm significance="preferred"><primary><option>--icmp-advert-entry</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option adds a Router Advertisement entry to an ICMP Router
Advertisement message. The parameter must be two
values separated by a comma. <replaceable>addr</replaceable> is
the router's IP and can be specified either as an IP address in
dot-decimal notation or as a hostname. <replaceable>pref</replaceable>
is the preference level for the specified IP. It must be a number
in the range [0&ndash;4294967295]. An example is
<option>--icmp-advert-entry 192.168.128.1,3</option>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--icmp-orig-time <replaceable>timestamp</replaceable></option> (ICMP Originate Timestamp)
<indexterm significance="preferred"><primary><option>--icmp-orig-time</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option sets the Originate Timestamp in ICMP Timestamp messages.
The Originate Timestamp is expressed as the number of milliseconds
since midnight UTC and it corresponds to the time the sender
last touched the Timestamp message before its transmission.
<replaceable>timestamp</replaceable> can be specified as a regular
time (e.g. <literal>10s</literal>, <literal>3h</literal>, <literal>1000ms</literal>), or the special string
<literal>now</literal>. You can add or subtract
values from <literal>now</literal>, for example
<option>--icmp-orig-time now-2s</option>,
<option>--icmp-orig-time now+1h</option>,
<option>--icmp-orig-time now+200ms</option>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--icmp-recv-time <replaceable>timestamp</replaceable></option> (ICMP Receive Timestamp)
<indexterm significance="preferred"><primary><option>--icmp-recv-time</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option sets the Receive Timestamp in ICMP Timestamp messages.
The Receive Timestamp is expressed as the number of milliseconds
since midnight UTC and it corresponds to the time the echoer
first touched the Timestamp message on receipt.
<replaceable>timestamp</replaceable> is as with
<option>--icmp-orig-time</option>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--icmp-trans-time <replaceable>timestamp</replaceable></option> (ICMP Transmit Timestamp)
<indexterm significance="preferred"><primary><option>--icmp-trans-time</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option sets the Transmit Timestamp in ICMP Timestamp messages.
The Transmit Timestamp is expressed as the number of milliseconds
since midnight UTC and it corresponds to the time the echoer
last touched the Timestamp message before its transmission.
<replaceable>timestamp</replaceable> is as with
<option>--icmp-orig-time</option>.
</para>
</listitem>
</varlistentry>
</variablelist>
<refsect2 id="nping-man-icmp-types">
<indexterm class="startofrange" id="nping-man-icmp-types-indexterm"><primary>ICMP types</primary><secondary>mnemonics of, in Nping</secondary></indexterm>
<title>ICMP Types</title>
<para>
These identifiers may be used as mnemonics for the ICMP type numbers given
to the
<option>--icmp-type</option><indexterm><primary><option>--icmp-type</option> (Nping option)</primary></indexterm>
option. In general there are three forms of each identifier: the full name
(e.g. <literal>destination-unreachable</literal>), the short name (e.g.
<literal>dest-unr</literal>), or the initials (e.g. <literal>du</literal>).
In ICMP types that request something, the word "request" is omitted.
</para>
<variablelist>
<varlistentry>
<term><literal>echo-reply</literal></term>
<term><literal>echo-rep</literal></term>
<term><literal>er</literal></term>
<listitem>
<para>
Echo Reply (type 0). This message is sent in response to an Echo
Request message.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>destination-unreachable</literal></term>
<term><literal>dest-unr</literal></term>
<term><literal>du</literal></term>
<listitem>
<para>
Destination Unreachable (type 3). This message indicates that
a datagram could not be delivered to its destination.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>source-quench</literal></term>
<term><literal>sour-que</literal></term>
<term><literal>sq</literal></term>
<listitem>
<para>
Source Quench (type 4). This message is used by a congested
IP device to tell other device that is sending packets too fast
and that it should slow down.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>redirect</literal></term>
<term><literal>redi</literal></term>
<term><literal>r</literal></term>
<listitem>
<para>
Redirect (type 5). This message is normally used by routers
to inform a host that there is a better route to use for sending
datagrams. See also the <option>--icmp-redirect-addr</option>
option.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>echo-request</literal></term>
<term><literal>echo</literal></term>
<term><literal>e</literal></term>
<listitem>
<para>
Echo Request (type 8). This message is used to test the
connectivity of another device on a network.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>router-advertisement</literal></term>
<term><literal>rout-adv</literal></term>
<term><literal>ra</literal></term>
<listitem>
<para>
Router Advertisement (type 9). This message is used by
routers to let hosts know of their existence and capabilities. See
also the <option>--icmp-advert-lifetime</option> option.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>router-solicitation</literal></term>
<term><literal>rout-sol</literal></term>
<term><literal>rs</literal></term>
<listitem>
<para>
Router Solicitation (type 10). This message is used by hosts
to request Router Advertisement messages from any listening
routers.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>time-exceeded</literal></term>
<term><literal>time-exc</literal></term>
<term><literal>te</literal></term>
<listitem>
<para>
Time Exceeded (type 11). This message is generated by some
intermediate device (normally a router) to indicate that a datagram
has been discarded before reaching its destination because the
IP TTL expired.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>parameter-problem</literal></term>
<term><literal>member-pro</literal></term>
<term><literal>pp</literal></term>
<listitem>
<para>
Parameter Problem (type 12). This message is used when a device
finds a problem with a parameter in an IP header and it cannot
continue processing it. See also the
<option>--icmp-param-pointer</option> option.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>timestamp</literal></term>
<term><literal>time</literal></term>
<term><literal>tm</literal></term>
<listitem>
<para>
Timestamp Request (type 13). This message is used to request
a device to send a timestamp value for propagation time
calculation and clock synchronization. See also the
<option>--icmp-orig-time</option>,
<option>--icmp-recv-time</option>, and
<option>--icmp-trans-time</option>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>timestamp-reply</literal></term>
<term><literal>time-rep</literal></term>
<term><literal>tr</literal></term>
<listitem>
<para>
Timestamp Reply (type 14). This message is sent in response
to a Timestamp Request message.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>information</literal></term>
<term><literal>info</literal></term>
<term><literal>i</literal></term>
<listitem>
<para>
Information Request (type 15). This message is now obsolete
but it was originally used to request configuration information
from another device.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>information-reply</literal></term>
<term><literal>info-rep</literal></term>
<term><literal>ir</literal></term>
<listitem>
<para>
Information Reply (type 16). This message is now obsolete but
it was originally sent in response to an Information Request
message to provide configuration information.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>mask-request</literal></term>
<term><literal>mask</literal></term>
<term><literal>m</literal></term>
<listitem>
<para>
Address Mask Request (type 17). This message is used to
ask a device to send its subnet mask.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>mask-reply</literal></term>
<term><literal>mask-rep</literal></term>
<term><literal>mr</literal></term>
<listitem>
<para>
Address Mask Reply (type 18). This message contains a subnet
mask and is sent in response to a Address Mask Request message.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>traceroute</literal></term>
<term><literal>trace</literal></term>
<term><literal>tc</literal></term>
<listitem>
<para>
Traceroute (type 30). This message is normally sent
by an intermediate device when it receives an IP datagram
with a traceroute option. ICMP Traceroute messages are still
experimental, see
RFC 1393<indexterm><primary>RFC 1393</primary></indexterm>
for more information.
</para>
</listitem>
</varlistentry>
</variablelist>
<indexterm class="endofrange" startref="nping-man-icmp-types-indexterm"/>
</refsect2>
<refsect2 id="nping-man-icmp-codes">
<indexterm class="startofrange" id="nping-man-icmp-codes-indexterm"><primary>ICMP codes</primary><secondary>mnemonics of, in Nping</secondary></indexterm>
<title>ICMP Codes</title>
<para>
These identifiers may be used as mnemonics for the ICMP code numbers given
to the
<option>--icmp-code</option><indexterm><primary><option>--icmp-code</option> (Nping option)</primary></indexterm>
option. They are listed by the ICMP type they correspond to.
</para>
<refsect3>
<title>Destination Unreachable</title>
<variablelist>
<varlistentry>
<term><literal>network-unreachable</literal></term>
<term><literal>netw-unr</literal></term>
<term><literal>net</literal></term>
<listitem>
<para>
Code 0. Datagram could not be delivered to its destination
network (probably due to some routing problem).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>host-unreachable</literal></term>
<term><literal>host-unr</literal></term>
<term><literal>host</literal></term>
<listitem>
<para>
Code 1. Datagram was delivered to the destination network but it
was impossible to reach the specified host (probably due to some
routing problem).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>protocol-unreachable</literal></term>
<term><literal>prot-unr</literal></term>
<term><literal>proto</literal></term>
<listitem>
<para>
Code 2. The protocol specified in the Protocol field of the IP
datagram is not supported by the host to which the datagram was
delivered.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>port-unreachable</literal></term>
<term><literal>port-unr</literal></term>
<term><literal>port</literal></term>
<listitem>
<para>
Code 3. The TCP/UDP destination port was invalid.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>needs-fragmentation</literal></term>
<term><literal>need-fra</literal></term>
<term><literal>frag</literal></term>
<listitem>
<para>
Code 4. Datagram had the DF bit set but it was too large for the
MTU of the next physical network so it had to be dropped.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>source-route-failed</literal></term>
<term><literal>sour-rou</literal></term>
<term><literal>routefail</literal></term>
<listitem>
<para>
Code 5. IP datagram had a Source Route option but a router
couldn't pass it to the next hop.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>network-unknown</literal></term>
<term><literal>netw-unk</literal></term>
<term><literal>net?</literal></term>
<listitem>
<para>
Code 6. Destination network is unknown. This code is never used.
Instead, Network Unreachable is used.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>host-unknown</literal></term>
<term><literal>host-unk</literal></term>
<term><literal>host?</literal></term>
<listitem>
<para>
Code 7. Specified host is unknown. Usually generated by a router
local to the destination host to inform of a bad address.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>host-isolated</literal></term>
<term><literal>host-iso</literal></term>
<term><literal>isolated</literal></term>
<listitem>
<para>
Code 8. Source Host Isolated. Not used.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>network-prohibited</literal></term>
<term><literal>netw-pro</literal></term>
<term><literal>!net</literal></term>
<listitem>
<para>
Code 9. Communication with destination network is
administratively prohibited (source device is not allowed to send
packets to the destination network).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>host-prohibited</literal></term>
<term><literal>host-pro</literal></term>
<term><literal>!host</literal></term>
<listitem>
<para>
Code 10. Communication with destination host is administratively
prohibited. (The source device is allowed to send packets to the
destination network but not to the destination device.)
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>network-tos</literal></term>
<term><literal>unreachable-network-tos</literal></term>
<term><literal>netw-tos</literal></term>
<term><literal>tosnet</literal></term>
<listitem>
<para>
Code 11. Destination network unreachable because it cannot
provide the type of service specified in the IP TOS field.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>host-tos</literal></term>
<term><literal>unreachable-host-tos</literal></term>
<term><literal>toshost</literal></term>
<listitem>
<para>
Code 12. Destination host unreachable because it cannot provide
the type of service specified in the IP TOS field.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>communication-prohibited</literal></term>
<term><literal>comm-pro</literal></term>
<term><literal>!comm</literal></term>
<listitem>
<para>
Code 13. Datagram could not be forwarded due to filtering that
blocks the message based on its contents.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>host-precedence-violation</literal></term>
<term><literal>precedence-violation</literal></term>
<term><literal>prec-vio</literal></term>
<term><literal>violation</literal></term>
<listitem>
<para>
Code 14. Precedence value in the IP TOS field is not permitted.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>precedence-cutoff</literal></term>
<term><literal>prec-cut</literal></term>
<term><literal>cutoff</literal></term>
<listitem>
<para>
Code 15. Precedence value in the IP TOS field is lower than the
minimum allowed for the network.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect3>
<refsect3>
<title>Redirect</title>
<variablelist>
<varlistentry>
<term><literal>redirect-network</literal></term>
<term><literal>redi-net</literal></term>
<term><literal>net</literal></term>
<listitem>
<para>
Code 0. Redirect all future datagrams with the same destination
network as the original datagram, to the router specified in the
Address field. The use of this code is prohibited by
RFC 1812.<indexterm><primary>RFC 1812</primary></indexterm>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>redirect-host</literal></term>
<term><literal>redi-host</literal></term>
<term><literal>host</literal></term>
<listitem>
<para>
Code 1. Redirect all future datagrams with the same destination
host as the original datagram, to the router specified in the
Address field.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>redirect-network-tos</literal></term>
<term><literal>redi-ntos</literal></term>
<term><literal>redir-ntos</literal></term>
<listitem>
<para>
Code 2. Redirect all future datagrams with the same destination
network and IP TOS value as the original datagram, to the router
specified in the Address field. The use of this code is
prohibited by RFC 1812.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>redirect-host-tos</literal></term>
<term><literal>redi-htos</literal></term>
<term><literal>redir-htos</literal></term>
<listitem>
<para>
Code 3. Redirect all future datagrams with the same destination
host and IP TOS value as the original datagram, to the router
specified in the Address field.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect3>
<refsect3>
<title>Router Advertisement</title>
<variablelist>
<varlistentry>
<term><literal>normal-advertisement</literal></term>
<term><literal>norm-adv</literal></term>
<term><literal>normal</literal></term>
<term><literal>zero</literal></term>
<term><literal>default</literal></term>
<term><literal>def</literal></term>
<listitem>
<para>
Code 0. Normal router advertisement. In Mobile IP: Mobility agent
can act as a router for IP datagrams not related to mobile nodes.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>not-route-common-traffic</literal></term>
<term><literal>not-rou</literal></term>
<term><literal>mobile-ip</literal></term>
<term><literal>!route</literal></term>
<term><literal>!commontraffic</literal></term>
<listitem>
<para>
Code 16. Used for Mobile IP. The mobility agent does not route
common traffic. All foreign agents must forward to a default
router any datagrams received from a registered mobile node
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect3>
<refsect3>
<title>Time Exceeded</title>
<variablelist>
<varlistentry>
<term><literal>ttl-exceeded-in-transit</literal></term>
<term><literal>ttl-exc</literal></term>
<term><literal>ttl-transit</literal></term>
<listitem>
<para>
Code 0. IP Time To Live expired during transit.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>fragment-reassembly-time-exceeded</literal></term>
<term><literal>frag-exc</literal></term>
<term><literal>frag-time</literal></term>
<listitem>
<para>
Code 1. Fragment reassembly time has been exceeded.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect3>
<refsect3>
<title>Parameter Problem</title>
<variablelist>
<varlistentry>
<term><literal>pointer-indicates-error</literal></term>
<term><literal>poin-ind</literal></term>
<term><literal>pointer</literal></term>
<listitem>
<para>
Code 0. The pointer field indicates the location of the problem.
See the <option>--icmp-param-pointer</option> option.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>missing-required-option</literal></term>
<term><literal>miss-option</literal></term>
<term><literal>option-missing</literal></term>
<listitem>
<para>
Code 1. IP datagram was expected to have an option that is not
present.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>bad-length</literal></term>
<term><literal>bad-len</literal></term>
<term><literal>badlen</literal></term>
<listitem>
<para>
Code 2. The length of the IP datagram is incorrect.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect3>
<!--
<refsect3>
<title>ICMP Security Failures Messages (Experimental)</title>
<variablelist>
<varlistentry>
<term><literal>bad-spi</literal></term>
<term><literal>badspi</literal></term>
<term><literal>!spi</literal></term>
<listitem>
<para>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>authentication-failed</literal></term>
<term><literal>auth-fai</literal></term>
<term><literal>auth-failed</literal></term>
<term><literal>authfail</literal></term>
<term><literal>!auth</literal></term>
<listitem>
<para>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>decompression-failed</literal></term>
<term><literal>deco-fai</literal></term>
<term><literal>decom-failed</literal></term>
<term><literal>!decompress</literal></term>
<term><literal>!decompression</literal></term>
<listitem>
<para>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>decryption-failed</literal></term>
<term><literal>decr-fai</literal></term>
<term><literal>decrypt-failed</literal></term>
<term><literal>!decrypt</literal></term>
<term><literal>!decryption</literal></term>
<listitem>
<para>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>need-authentication</literal></term>
<term><literal>need-aut</literal></term>
<term><literal>need-auth</literal></term>
<term><literal>auth-needed</literal></term>
<term><literal>!auth</literal></term>
<listitem>
<para>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>need-authorization</literal></term>
<term><literal>need-author</literal></term>
<term><literal>authorization-needed</literal></term>
<term><literal>author-needed</literal></term>
<term><literal>!author</literal></term>
<term><literal>!authorization</literal></term>
<listitem>
<para>
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect3>
-->
<indexterm class="endofrange" startref="nping-man-icmp-types-indexterm"/>
</refsect2>
</refsect1>
<!-- ARP MODE ************************************************************* -->
<refsect1 id="nping-man-arp-mode">
<title>ARP Mode</title>
<variablelist>
<varlistentry>
<term>
<option>--arp-type <replaceable>type</replaceable></option> (ICMP Type)
<indexterm significance="preferred"><primary><option>--arp-type</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option specifies which type of ARP messages should be
generated. <replaceable>type</replaceable> can be supplied in
two different ways. You can use the
<ulink url="http://www.iana.org/assignments/arp-parameters/">official
numbers assigned by IANA</ulink>
(e.g. <option>--arp-type 1</option> for ARP Request), or you can use
one of the mnemonics from <xref linkend="nping-man-arp-types"/>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--arp-sender-mac <replaceable>mac</replaceable></option> (Sender MAC address)
<indexterm significance="preferred"><primary><option>--arp-sender-mac</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option sets the Sender Hardware Address field of the ARP header.
Although ARP supports many types of link layer addresses, currently
Nping only supports MAC addresses.
<replaceable>mac</replaceable> must be specified using the
traditional MAC notation (e.g. <literal>00:0a:8a:32:f4:ae</literal>). You can also use
hyphens as separators (e.g. <literal>00-0a-8a-32-f4-ae</literal>).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--arp-sender-ip <replaceable>addr</replaceable></option> (Sender IP address)
<indexterm significance="preferred"><primary><option>--arp-sender-ip</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option sets the Sender IP field of the ARP header.
<replaceable>addr</replaceable> can be given as an IPv4 address or a
hostname.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--arp-target-mac <replaceable>mac</replaceable></option> (target MAC address)
<indexterm significance="preferred"><primary><option>--arp-target-mac</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option sets the Target Hardware Address field of the ARP header.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--arp-target-ip <replaceable>addr</replaceable></option> (target ip address)
<indexterm significance="preferred"><primary><option>--arp-target-ip</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option sets the Target IP field of the ARP header.
</para>
</listitem>
</varlistentry>
</variablelist>
<refsect2 id="nping-man-arp-types">
<indexterm class="startofrange" id="nping-man-arp-types-indexterm"><primary>ARP types</primary><secondary>mnemonics of, in Nping</secondary></indexterm>
<title>ARP Types</title>
<para>
These identifiers may be used as mnemonics for the ARP type numbers given
to the
<option>--arp-type</option><indexterm><primary><option>--arp-type</option> (Nping option)</primary></indexterm>
option.
</para>
<variablelist>
<varlistentry>
<term><literal>arp-request</literal></term>
<term><literal>arp</literal></term>
<term><literal>a</literal></term>
<listitem>
<para>
ARP Request (type 1). ARP requests are used to translate network
layer addresses (normally IP addresses) to link layer addresses
(usually MAC addresses). Basically, and ARP request is a
broadcasted message that asks the host in the same network
segment that has a given IP address to provide its MAC address.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>arp-reply</literal></term>
<term><literal>arp-rep</literal></term>
<term><literal>ar</literal></term>
<listitem>
<para>
ARP Reply (type 2). An ARP reply is a message that a host sends in
response to an ARP request to provide its link layer address.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>rarp-request</literal></term>
<term><literal>rarp</literal></term>
<term><literal>r</literal></term>
<listitem>
<para>
RARP Requests (type 3). RARP requests are used to translate a
link layer address (normally a MAC address) to a network layer
address (usually an IP address). Basically a RARP request is a
broadcasted message sent by a host that wants to know his own IP
address because it doesn't have any. It was the first protocol
designed to solve the bootstrapping problem. However, RARP is now
obsolete and DHCP is used instead. For more information about
RARP see
RFC 903.<indexterm><primary>RFC 903</primary></indexterm>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>rarp-reply</literal></term>
<term><literal>rarp-rep</literal></term>
<term><literal>rr</literal></term>
<listitem>
<para>
RARP Reply (type 4). A RARP reply is a message sent in response
to a RARP request to provide an IP address to the host that sent
the RARP request in the first place.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>drarp-request</literal></term>
<term><literal>drarp</literal></term>
<term><literal>d</literal></term>
<listitem>
<para>
Dynamic RARP Request (type 5). Dynamic RARP is an extension to
RARP used to obtain or assign a network layer address from a
fixed link layer address. DRARP was used mainly in Sun
Microsystems platforms in the late 90's but now it's no longer
used. See
RFC 1931<indexterm><primary>RFC 1931</primary></indexterm>
for more information.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>drarp-reply</literal></term>
<term><literal>drarp-rep</literal></term>
<term><literal>dr</literal></term>
<listitem>
<para>
Dynamic RARP Reply (type 6). A DRARP reply is a message sent in
response to a RARP request to provide network layer address.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>drarp-error</literal></term>
<term><literal>drarp-err</literal></term>
<term><literal>de</literal></term>
<listitem>
<para>
DRARP Error (type 7). DRARP Error messages are usually sent in
response to DRARP requests to inform of some error. In DRARP
Error messages, the Target Protocol Address field is used to
carry an error code (usually in the first byte). The error code
is intended to tell why no target protocol address is being
returned. For more information see RFC 1931.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>inarp-request</literal></term>
<term><literal>inarp</literal></term>
<term><literal>i</literal></term>
<listitem>
<para>
Inverse ARP Request (type 8). InARP requests are used to
translate a link layer address to a network layer address. It is
similar to RARP request but in this case, the sender of the InARP
request wants to know the network layer address of another node,
not its own address. InARP is mainly used in Frame Relay and ATM
networks. For more information see
RFC 2390.<indexterm><primary>RFC 2390</primary></indexterm>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>inarp-reply</literal></term>
<term><literal>inarp-rep</literal></term>
<term><literal>ir</literal></term>
<listitem>
<para>
Inverse ARP Reply (type 9). InARP reply messages are sent in
response to InARP requests to provide the network layer address
associated with the host that has a given link layer address.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>arp-nak</literal></term>
<term><literal>an</literal></term>
<listitem>
<para>
ARP NAK (type 10). ARP NAK messages are an extension to the
ATMARP protocol and they are used to improve the robustness of
the ATMARP server mechanism. With ARP NAK, a client can determine
the difference between a catastrophic server failure and an
ATMARP table lookup failure. See
RFC 1577<indexterm><primary>RFC 1577</primary></indexterm>
for more information.
</para>
</listitem>
</varlistentry>
</variablelist>
<indexterm class="endofrange" startref="nping-man-arp-types-indexterm"/>
</refsect2>
</refsect1>
<!-- IPv4 OPTIONS ********************************************************** -->
<refsect1 id="nping-man-ip-options">
<title>IPv4 Options</title>
<variablelist>
<varlistentry>
<term>
<option>-S <replaceable>addr</replaceable></option>,
<option>--source-ip <replaceable>addr</replaceable></option> (Source IP Address)
<indexterm significance="preferred"><primary><option>--source-ip</option> (Nping option)</primary></indexterm>
<indexterm significance="preferred"><primary><option>-S</option> (Nping option)</primary><see><option>--source-ip</option></see></indexterm>
</term>
<listitem>
<para>
Sets the source IP address. This option lets you specify a custom IP
address to be used as source IP address in sent packets. This
allows spoofing the sender of the packets.
<replaceable>addr</replaceable> can be an IPv4 address or a hostname.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--dest-ip <replaceable>addr</replaceable></option> (Destination IP Address)
<indexterm significance="preferred"><primary><option>--dest-ip</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
Adds a target to Nping's target list.
This option is provided for consistency but its use is deprecated
in favor of plain target specifications. See
<xref linkend="nping-man-target-specification"/>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--tos <replaceable>tos</replaceable></option> (Type of Service)
<indexterm significance="preferred"><primary><option>--tos</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
Sets the IP TOS field. The TOS field is used to carry information
to provide quality of service features. It is normally used to
support a technique called Differentiated Services. See
RFC 2474<indexterm><primary>RFC 2474</primary></indexterm>
for
more information. <replaceable>tos</replaceable> must be a number
in the range [0&ndash;255].
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--id <replaceable>id</replaceable></option> (Identification)
<indexterm significance="preferred"><primary><option>--id</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
Sets the IPv4 Identification field. The Identification field is a
16-bit value that is common to all fragments belonging to a particular
message. The value is used by the receiver to reassemble the
original message from the fragments received. <replaceable>id</replaceable>
must be a number in the range [0&ndash;65535].
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--df</option> (Don't Fragment)
<indexterm significance="preferred"><primary><option>--df</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
Sets the Don't Fragment bit in sent packets. When an
IP datagram has its DF flag set, intermediate devices are not
allowed to fragment it so if it needs to travel across a network
with a MTU smaller that datagram length the datagram will have
to be dropped. Normally an ICMP Destination Unreachable message
is generated and sent back to the sender.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--mf</option> (More Fragments)
<indexterm significance="preferred"><primary><option>--mf</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
Sets the More Fragments bit in sent packets. The MF
flag is set to indicate the receiver that the current datagram is
a fragment of some larger datagram. When set to zero it indicates
that the current datagram is either the last fragment in the set
or that it is the only fragment.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--ttl <replaceable>hops</replaceable></option> (Time To Live)
<indexterm significance="preferred"><primary><option>--ttl</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
Sets the IPv4 Time-To-Live (TTL) field in sent packets to the given
value. The TTL field specifies how long the datagram is allowed
to exist on the network. It was originally intended to represent
a number of seconds but it actually represents the number of
hops a packet can traverse before being dropped. The TTL tries to
avoid a situation in which undeliverable datagrams keep being
forwarded from one router to another endlessly.
<replaceable>hops</replaceable> must be a number in the range [0&ndash;255].
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--badsum-ip</option> (Invalid IP checksum)
<indexterm significance="preferred"><primary><option>--badsum-ip</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
Asks Nping to use an invalid IP checksum for packets sent to
target hosts. Note that some systems (like most Linux kernels),
may fix the checksum before placing the packet on the wire, so
even if Nping shows the incorrect checksum in its output, the
packets may be transparently corrected by the kernel.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--ip-options <replaceable>S|R [route]|L [route]|T|U ...</replaceable></option>,
<option>--ip-options <replaceable>hex string</replaceable></option> (IP Options)
<indexterm significance="preferred"><primary><option>--ip-options</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
The IP protocol offers several options which may be placed in
packet headers. Unlike the ubiquitous TCP options, IP options are
rarely seen due to practicality and security concerns. In fact,
many Internet routers block the most dangerous options such as
source routing. Yet options can still be useful in some cases for
determining and manipulating the network route to target machines.
For example, you may be able to use the record route option to
determine a path to a target even when more traditional
traceroute-style approaches fail. Or if your packets are being
dropped by a certain firewall, you may be able to specify a
different route with the strict or loose source routing options.
</para>
<para>
The most powerful way to specify IP options is to simply pass in hexadecimal data
as the argument to <option>--ip-options</option>. Precede each hex byte value
with <literal>\x</literal>. You may repeat certain characters by
following them with an asterisk and then the number of times you
wish them to repeat. For example,
<literal>\x01\x07\x04\x00*4</literal> is the same as
<literal>\x01\x07\x04\x00\x00\x00\x00</literal>.
</para>
<para>
Note that if you specify a number of bytes that is not a multiple
of four, an incorrect IP header length will be set in the IP
packet. The reason for this is that the IP header length field
can only express multiples of four. In those cases, the length is
computed by dividing the header length by 4 and rounding down.
This will
affect the way the header that follows the IP header is
interpreted, showing bogus information in Nping or in the output
of any sniffer. Although this kind of situation might be useful
for some stack stress tests, users would normally want to
specify explicit padding, so the correct header length is set.
</para>
<para>
Nping also offers a shortcut mechanism for specifying options.
Simply pass the letter <literal>R</literal>, <literal>T</literal>, or <literal>U</literal> to request record-route,
record-timestamp, or both options together, respectively. Loose
or strict source routing may be specified with an L or S followed
by a space and then a space-separated list of IP addresses.
</para>
<para>
For more information and examples of using IP options with Nping,
see the mailing list post at
<ulink url="http://seclists.org/nmap-dev/2006/q3/0052.html"/>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--mtu <replaceable>size</replaceable></option> (Maximum Transmission Unit)
<indexterm significance="preferred"><primary><option>--mtu</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option sets a fictional MTU in Nping so IP datagrams larger than
<replaceable>size</replaceable> are fragmented before transmission.
<replaceable>size</replaceable> must be specified in bytes and
corresponds to the number of octets that can be carried on a
single link-layer frame.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<!-- IPv6 OPTIONS ********************************************************** -->
<refsect1 id="nping-man-ip6-options">
<title>IPv6 Options</title>
<variablelist>
<varlistentry>
<term>
<option>-6</option>,
<option>--ipv6</option> (Use IPv6)
<indexterm significance="preferred"><primary><option>--ipv6</option> (Nping option)</primary></indexterm>
<indexterm significance="preferred"><primary><option>-6</option> (Nping option)</primary><see><option>--ipv6</option></see></indexterm>
</term>
<listitem>
<para>
Tells Nping to use IP version 6 instead of the default IPv4.
It is generally a good idea to specify this option as early as
possible in the command line so Nping can parse it soon and know in
advance that the rest of the parameters refer to IPv6. The command
syntax is the same as usual except that you also add the <option>-6</option> option.
Of course, you must use IPv6 syntax if you specify an address
rather than a hostname. An address might look like
<option>3ffe:7501:4819:2000:210:f3ff:fe03:14d0</option>, so hostnames are
recommended.
</para>
<para>
While IPv6 hasn't exactly taken the world by storm, it gets
significant use in some (usually Asian) countries and most modern
operating systems support it. To use Nping with IPv6, both the
source and target of your packets must be configured for IPv6. If your
ISP (like most of them) does not allocate IPv6 addresses to you,
free tunnel brokers are widely available and work fine with Nping.
You can use the free IPv6 tunnel broker service at
<ulink url="http://www.tunnelbroker.net"/>.
</para>
<para>
Please note that IPv6 support is still highly experimental and
many modes and options may not work with it.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-S <replaceable>addr</replaceable></option>,
<option>--source-ip <replaceable>addr</replaceable></option> (Source IP Address)
<indexterm significance="preferred"><primary><option>--source-ip</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
Sets the source IP address. This option lets you specify a custom IP
address to be used as source IP address in sent packets. This
allows spoofing the sender of the packets.
<replaceable>addr</replaceable> can be an IPv6 address or a hostname.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--dest-ip <replaceable>addr</replaceable></option> (Destination IP Address)
<indexterm significance="preferred"><primary><option>--dest-ip</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
Adds a target to Nping's target list.
This option is provided for consistency but its use is deprecated
in favor of plain target specifications. See
<xref linkend="nping-man-target-specification"/>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--flow <replaceable>label</replaceable></option> (Flow Label)
<indexterm significance="preferred"><primary><option>--flow</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
Sets the IPv6 Flow Label. The Flow Label field is 20 bits long and is
intended to provide certain quality-of-service properties for
real-time datagram delivery. However, it has not been widely
adopted, and not all routers or endpoints support it. Check
RFC 2460<indexterm><primary>RFC 2560</primary></indexterm>
for more information. <replaceable>label</replaceable> must be an
integer in the range [0&ndash;1048575].
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--traffic-class <replaceable>class</replaceable></option> (Traffic Class)
<indexterm significance="preferred"><primary><option>--traffic-class</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
Sets the IPv6 Traffic Class. This field is similar to the TOS field in
IPv4, and is intended to provide the Differentiated Services
method, enabling scalable service discrimination in the Internet
without the need for per-flow state and signaling at every hop. Check
RFC 2474<indexterm><primary>RFC 2474</primary></indexterm>
for more information. <replaceable>class</replaceable> must
be an integer in the range [0&ndash;255].
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--hop-limit <replaceable>hops</replaceable></option> (Hop Limit)
<indexterm significance="preferred"><primary><option>--hop-limit</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
<indexterm><primary>hop limit (IPv6)</primary><seealso>TTL</seealso></indexterm>
Sets the IPv6 Hop Limit field in sent packets to the given
value. The Hop Limit field specifies how long the datagram is allowed
to exist on the network. It represents the number of hops a packet
can traverse before being dropped. As with the TTL in IPv4, IPv6 Hop Limit
tries to avoid a situation in which undeliverable datagrams keep being
forwarded from one router to another endlessly.
<replaceable>hops</replaceable> must be a number in the range [0&ndash;255].
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<!-- ETHERNET OPTIONS ***************************************************** -->
<refsect1 id="nping-man-ethernet-options">
<title>Ethernet Options</title>
<para>
In most cases Nping sends packets at the raw IP level. This means that Nping
creates its own IP packets and transmits them through a raw socket. However,
in some cases it may be necessary to send packets at the raw Ethernet level.
This happens, for example, when Nping is run under Windows (as Microsoft
has disabled raw socket support since Windows XP SP2), or when Nping is
asked to send ARP packets.
Since in some cases it is necessary to construct ethernet frames, Nping
offers some options to manipulate the different fields.
</para>
<variablelist>
<varlistentry>
<term>
<option>--dest-mac <replaceable>mac</replaceable></option> (Ethernet Destination MAC Address)
<indexterm significance="preferred"><primary><option>--dest-mac</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option sets the destination MAC address that should be set in
outgoing Ethernet frames. This is useful in case Nping can't
determine the next hop's MAC address or when you want to route
probes through a router other than the configured default
gateway. The MAC address should have the usual format of
six colon-separated bytes, e.g. <literal>00:50:56:d4:01:98</literal>.
Alternatively, hyphens may be used instead of colons.
Use the word <literal>random</literal> or <literal>rand</literal> to
generate a random address, and <literal>broadcast</literal> or
<literal>bcast</literal> to use ff:ff:ff:ff:ff:ff.
If you set up a bogus destination MAC address your probes may not
reach the intended targets.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--source-mac <replaceable>mac</replaceable></option> (Ethernet Source MAC Address)
<indexterm significance="preferred"><primary><option>--source-mac</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option sets the source MAC address that should be set in
outgoing Ethernet frames. This is useful in case Nping can't
determine your network interface MAC address or when you want to
inject traffic into the network while hiding your network card's real
address. The syntax is the same as for <literal>--dest-mac</literal>.
If you set up a bogus source MAC address
you may not receive probe replies.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--ether-type <replaceable>type</replaceable></option> (Ethertype)
<indexterm significance="preferred"><primary><option>--ether-type</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option sets the Ethertype field of the ethernet frame.
The Ethertype is used to indicate which protocol is encapsulated
in the payload. <replaceable>type</replaceable> can be supplied in
two different ways. You can use the
<ulink url="http://standards.ieee.org/regauth/ethertype/eth.txt">official
numbers listed by the IEEE</ulink>
(e.g. <option>--ether-type 0x0800</option> for IP version 4),
or one of the mnemonics from
<xref linkend="nping-man-ether-types" xrefstyle="template:the section called &#x201c;%t&#x201d;"/>.
<!-- Hide the page number, but also include the section title. xrefstyle="select: label nopage" doesn't work here. -->
</para>
</listitem>
</varlistentry>
</variablelist>
<refsect2 id="nping-man-ether-types">
<indexterm class="startofrange" id="nping-man-arp-ether-indexterm"><primary>Ethernet types</primary><secondary>mnemonics of, in Nping</secondary></indexterm>
<title>Ethernet Types</title>
<para>
These identifiers may be used as mnemonics for the Ethertype numbers given
to the
<option>--arp-type</option><indexterm><primary><option>--arp-type</option> (Nping option)</primary></indexterm>
option.
</para>
<variablelist>
<varlistentry>
<term><literal>ipv4</literal></term>
<term><literal>ip</literal></term>
<term><literal>4</literal></term>
<listitem>
<para>
Internet Protocol version 4 (type 0x0800).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>ipv6</literal></term>
<term><literal>6</literal></term>
<listitem>
<para>
Internet Protocol version 6 (type 0x86DD).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>arp</literal></term>
<listitem>
<para>
Address Resolution Protocol (type 0x0806).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>rarp</literal></term>
<listitem>
<para>
Reverse Address Resolution Protocol (type 0x8035).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>frame-relay</literal></term>
<term><literal>frelay</literal></term>
<term><literal>fr</literal></term>
<listitem>
<para>
Frame Relay (type 0x0808).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>ppp</literal></term>
<listitem>
<para>
Point-to-Point Protocol (type 0x880B).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>gsmp</literal></term>
<listitem>
<para>
General Switch Management Protocol (type 0x880C).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>mpls</literal></term>
<listitem>
<para>
Multiprotocol Label Switching (type 0x8847).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>mps-ual</literal></term>
<term><literal>mps</literal></term>
<listitem>
<para>
Multiprotocol Label Switching with Upstream-assigned Label (type 0x8848).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>mcap</literal></term>
<listitem>
<para>
Multicast Channel Allocation Protocol (type 0x8861).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>pppoe-discovery</literal></term>
<term><literal>pppoe-d</literal></term>
<listitem>
<para>
PPP over Ethernet Discovery Stage (type 0x8863).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>pppoe-session</literal></term>
<term><literal>pppoe-s</literal></term>
<listitem>
<para>
PPP over Ethernet Session Stage (type 0x8864).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>ctag</literal></term>
<listitem>
<para>
Customer VLAN Tag Type (type 0x8100).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>epon</literal></term>
<listitem>
<para>
Ethernet Passive Optical Network (type 0x8808).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>pbnac</literal></term>
<listitem>
<para>
Port-based network access control (type 0x888E).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>stag</literal></term>
<listitem>
<para>
Service VLAN tag identifier (type 0x88A8).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>ethexp1</literal></term>
<listitem>
<para>
Local Experimental Ethertype 1 (type 0x88B5).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>ethexp2</literal></term>
<listitem>
<para>
Local Experimental Ethertype 2 (type 0x88B6).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>ethoui</literal></term>
<listitem>
<para>
OUI Extended Ethertype (type 0x88B7).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>preauth</literal></term>
<listitem>
<para>
Pre-Authentication (type 0x88C7).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>lldp</literal></term>
<listitem>
<para>
Link Layer Discovery Protocol (type 0x88CC).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>mac-security</literal></term>
<term><literal>mac-sec</literal></term>
<term><literal>macsec</literal></term>
<listitem>
<para>
Media Access Control Security (type 0x88E5).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>mvrp</literal></term>
<listitem>
<para>
Multiple VLAN Registration Protocol (type 0x88F5).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>mmrp</literal></term>
<listitem>
<para>
Multiple Multicast Registration Protocol (type 0x88F6).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>frrr</literal></term>
<listitem>
<para>
Fast Roaming Remote Request (type 0x890D).
</para>
</listitem>
</varlistentry>
</variablelist>
<indexterm class="endofrange" startref="nping-man-ether-types-indexterm"/>
</refsect2>
</refsect1>
<!-- PAYLOAD OPTIONS ******************************************************* -->
<refsect1 id="nping-man-payload-options">
<title>Payload Options</title>
<variablelist>
<varlistentry>
<term>
<option>--data <replaceable>hex string</replaceable></option> (Append custom binary data to sent packets)
<indexterm significance="preferred"><primary><option>--data</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option lets you include binary data as payload in sent packets.
<replaceable>hex string</replaceable> may be specified in any of
the following formats: <literal>0xAABBCCDDEEFF<replaceable>...</replaceable></literal>,
<literal>AABBCCDDEEFF<replaceable>...</replaceable></literal> or
<literal>\xAA\xBB\xCC\xDD\xEE\xFF<replaceable>...</replaceable></literal>.
Examples of use are <option>--data 0xdeadbeef</option> and
<option>--data \xCA\xFE\x09</option>. Note that if you specify a
number like <literal>0x00ff</literal>
no byte-order conversion is performed. Make sure you specify
the information in the byte order expected by the receiver.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--data-string <replaceable>string</replaceable></option> (Append custom string to sent packets)
<indexterm significance="preferred"><primary><option>--data-string</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option lets you include a regular string as payload in
sent packets. <replaceable>string</replaceable> can
contain any string. However, note that some characters
may depend on your system's locale and the receiver may not
see the same information. Also, make sure you enclose the string
in double quotes and escape any special characters from the shell.
Example: <option>--data-string "Jimmy Jazz..."</option>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--data-length <replaceable>len</replaceable></option> (Append random data to sent packets)
<indexterm significance="preferred"><primary><option>--data-length</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option lets you include <replaceable>len</replaceable>
random bytes of data as payload in sent packets.
<replaceable>len</replaceable> must be an integer in the range
[0&ndash;65400]. However, values higher than 1400 are not recommended
because it may not be possible to transmit packets due to
network MTU limitations.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<!-- ECHO MODE ****************************************************** -->
<refsect1 id="nping-man-echo-mode">
<title>Echo Mode</title>
<para>
The "Echo Mode" is a novel technique implemented by Nping which lets users
see how network packets change in transit, from the host where they
originated to the target machine. Basically, the Echo mode turns Nping into
two different pieces: the Echo server and the Echo client. The Echo server
is a network service that has the ability to capture packets from the
network and send a copy ("echo them") to the originating client through a
side TCP channel. The Echo client is the part that generates such network
packets, transmits them to the server, and receives their echoed version
through a side TCP channel that it has previously established with the Echo
server.
</para>
<para>
This scheme lets the client see the differences between the packets that it
sends and what is actually received by the server. By having the server
send back copies of the received packets through the side channel, things
like NAT devices become immediately apparent to the client because it
notices the changes in the source IP address (and maybe even source
port). Other devices like those that perform traffic shaping, changing
TCP window sizes or adding TCP options transparently between hosts, turn up
too.
</para>
<para>
The Echo mode is also useful for troubleshooting routing and firewall issues.
Among other things, it can be used to determine if the traffic generated
by the Nping client is being dropped in transit and never gets to its
destination or if the responses are the ones that don't get back to it.
</para>
<para>
Internally, client and server communicate over an encrypted and
authenticated channel, using the Nping Echo Protocol (NEP), whose technical
specification can be found in
<ulink url="https://nmap.org/svn/nping/docs/EchoProtoRFC.txt"/>
</para>
<para>
The following paragraphs describe the different options available in Nping's
Echo mode.
</para>
<variablelist>
<varlistentry>
<term>
<option>--ec <replaceable>passphrase</replaceable></option>,
<option>--echo-client <replaceable>passphrase</replaceable></option> (Run Echo client)
<indexterm significance="preferred"><primary><option>--echo-client</option> (Nping option)</primary></indexterm>
<indexterm significance="preferred"><primary><option>--ec</option> (Nping option)</primary><see><option>--echo-client</option></see></indexterm>
</term>
<listitem>
<para>
This option tells Nping to run as an Echo client.
<replaceable>passphrase</replaceable> is a sequence of ASCII
characters that is used used to generate the cryptographic
keys needed for encryption and authentication in a given session.
The passphrase should be a secret that is also known by the server,
and it may contain any number of printable ASCII characters.
Passphrases that contain whitespace or special characters must be
enclosed in double quotes.
</para>
<para>
When running Nping as an Echo client, most options from the regular
raw probe modes apply. The client may be configured to send specific
probes using flags like <option>--tcp</option>,
<option>--icmp</option> or <option>--udp</option>. Protocol header
fields may be manipulated normally using the appropriate options
(e.g. <option>--ttl</option>, <option>--seq</option>,
<option>--icmp-type</option>, etc.). The only exceptions are
ARP-related flags, which are not supported in Echo mode, as protocols
like ARP are closely related to the data link layer and its probes
can't pass through different network segments.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--es <replaceable>passphrase</replaceable></option>,
<option>--echo-server <replaceable>passphrase</replaceable></option> (Run Echo server)
<indexterm significance="preferred"><primary><option>--echo-server</option> (Nping option)</primary></indexterm>
<indexterm significance="preferred"><primary><option>--es</option> (Nping option)</primary><see><option>--echo-server</option></see></indexterm>
</term>
<listitem>
<para>
This option tells Nping to run as an Echo server.
<replaceable>passphrase</replaceable> is a sequence of ASCII
characters that is used used to generate the cryptographic
keys needed for encryption and authentication in a given session.
The passphrase should be a secret that is also known by the clients,
and it may contain any number of printable ASCII characters.
Passphrases that contain whitespace or special characters must be
enclosed in double quotes. Note that although it is not recommended,
it is possible to use empty passphrases, supplying
<option>--echo-server ""</option>. However, if what you
want is to set up an open Echo server, it is better to use option
<option>--no-crypto</option>. See below for details.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--ep <replaceable>port</replaceable></option>,
<option>--echo-port <replaceable>port</replaceable></option> (Set Echo TCP port number)
<indexterm significance="preferred"><primary><option>--echo-port</option> (Nping option)</primary></indexterm>
<indexterm significance="preferred"><primary><option>--ep</option> (Nping option)</primary><see><option>--echo-port</option></see></indexterm>
</term>
<listitem>
<para>
This option asks Nping to use the specified TCP port number for the
Echo side channel connection. If this option is used with
<option>--echo-server</option>, it specifies the port on which the
server listens for connections. If it is used with
<option>--echo-client</option>, it specifies the port to connect to
on the remote host. By default, port number 9929 is used.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--nc</option>,
<option>--no-crypto</option> (Disable encryption and authentication)
<indexterm significance="preferred"><primary><option>--no-crypto</option> (Nping option)</primary></indexterm>
<indexterm significance="preferred"><primary><option>--nc</option> (Nping option)</primary><see><option>--no-crypto</option></see></indexterm>
</term>
<listitem>
<para>
This option asks Nping not to use any cryptographic operations during
an Echo session. In practical terms, this means that the Echo side
channel session data will be transmitted in the clear, and no
authentication will be performed by the server or client
during the session establishment phase. When <option>--no-crypto</option>
is used, the passphrase supplied with <option>--echo-server</option>
or <option>--echo-client</option> is ignored.
</para>
<para>
This option must be specified if Nping was compiled without
openSSL support. Note that, for technical reasons, a passphrase still
needs to be supplied after the --echo-client or --echo-server flags,
even though it will be ignored.
</para>
<para>
The --no-crypto flag might be useful when setting up a public Echo
server, because it allows users to connect to the Echo server without
the need for any passphrase or shared secret. However, it is strongly
recommended to not use --no-crypto unless absolutely necessary. Public
Echo servers should be configured to use the passphrase "public" or
the empty passphrase (--echo-server "") as the use of cryptography
does not only provide confidentiality and authentication but also
message integrity.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--once</option> (Serve one client and quit)
<indexterm significance="preferred"><primary><option>--once</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option asks the Echo server to quit after serving one client.
This is useful when only a single Echo session wants to be established
as it eliminates the need to access the remote host to shutdown the
server.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--safe-payloads</option> (Zero application data before echoing a packet)
<indexterm significance="preferred"><primary><option>--safe-payloads</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option asks the Echo server to erase any application layer data
found in client packets before echoing them. When the option is enabled,
the Echo server parses the packets received from Echo clients and tries
to determine if they contain data beyond the transport layer. If such
data is found, it is overwritten with zeroes before transmitting the
packets to the appropriate Echo client.
</para>
<para>
Echo servers can handle multiple simultaneous clients running
multiple echo sessions in parallel. In order to determine which packet
needs to be echoed to which client and through which session, the Echo
server uses an heuristic algorithm. Although we have taken every
security measure that we could think of to prevent that a client
receives an echoed packet that it did not generate, there is always
a risk that our algorithm makes a mistake and delivers a packet to
the wrong client. The --safe-payloads option is useful for public
echo servers or critical deployments where that kind of mistake
cannot be afforded.
</para>
</listitem>
</varlistentry>
</variablelist>
<para>
The following examples illustrate how Nping's Echo mode can be used
to discover intermediate devices.
</para>
<example id="nping-man-ex-echo1"><title>Discovering NAT devices</title>
<indexterm><primary><option>--echo-client</option> (Nping option)</primary><secondary>example of</secondary></indexterm>
<screen format="linespecific">
# <userinput>nping --echo-client "public" echo.nmap.org --udp </userinput>
Starting Nping ( https://nmap.org/nping )
SENT (1.0970s) UDP 10.1.20.128:53 &gt; 178.79.165.17:40125 ttl=64 id=32523 iplen=28
CAPT (1.1270s) UDP 80.38.10.21:45657 &gt; 178.79.165.17:40125 ttl=54 id=32523 iplen=28
RCVD (1.1570s) ICMP 178.79.165.17 &gt; 10.1.20.128 Port unreachable (type=3/code=3) ttl=49 id=16619 iplen=56
[...]
SENT (5.1020s) UDP 10.1.20.128:53 &gt; 178.79.165.17:40125 ttl=64 id=32523 iplen=28
CAPT (5.1335s) UDP 80.38.10.21:45657 &gt; 178.79.165.17:40125 ttl=54 id=32523 iplen=28
RCVD (5.1600s) ICMP 178.79.165.17 &gt; 10.1.20.128 Port unreachable (type=3/code=3) ttl=49 id=16623 iplen=56
Max rtt: 60.628ms | Min rtt: 58.378ms | Avg rtt: 59.389ms
Raw packets sent: 5 (140B) | Rcvd: 5 (280B) | Lost: 0 (0.00%)| Echoed: 5 (140B)
Tx time: 4.00459s | Tx bytes/s: 34.96 | Tx pkts/s: 1.25
Rx time: 5.00629s | Rx bytes/s: 55.93 | Rx pkts/s: 1.00
Nping done: 1 IP address pinged in 6.18 seconds
</screen>
</example>
<para>
The output clearly shows the presence of a NAT device in the client's local
network. Note how the captured packet (CAPT) differs from the SENT packet: the
source address for the original packets is in the reserved 10.0.0.0/8 range,
while the address seen by the server is 80.38.10.21, the Internet side address
of the NAT device. The source port was also modified by the device. The line
starting with RCVD corresponds to the responses generated by the TCP/IP stack
of the machine where the Echo server is run.
</para>
<example id="nping-man-ex-echo2"><title>Discovering a transparent proxy</title>
<screen format="linespecific">
# <userinput>nping --echo-client "public" echo.nmap.org --tcp -p80</userinput>
Starting Nping ( https://nmap.org/nping )
SENT (1.2160s) TCP 10.0.1.77:41659 &gt; 178.79.165.17:80 S ttl=64 id=3317 iplen=40 seq=567704200 win=1480
RCVD (1.2180s) TCP 178.79.165.17:80 &gt; 10.0.1.77:41659 SA ttl=128 id=13177 iplen=44 seq=3647106954 win=16384 &lt;mss 1460&gt;
SENT (2.2150s) TCP 10.0.1.77:41659 &gt; 178.79.165.17:80 S ttl=64 id=3317 iplen=40 seq=567704200 win=1480
SENT (3.2180s) TCP 10.0.1.77:41659 &gt; 178.79.165.17:80 S ttl=64 id=3317 iplen=40 seq=567704200 win=1480
SENT (4.2190s) TCP 10.0.1.77:41659 &gt; 178.79.165.17:80 S ttl=64 id=3317 iplen=40 seq=567704200 win=1480
SENT (5.2200s) TCP 10.0.1.77:41659 &gt; 178.79.165.17:80 S ttl=64 id=3317 iplen=40 seq=567704200 win=1480
Max rtt: 2.062ms | Min rtt: 2.062ms | Avg rtt: 2.062ms
Raw packets sent: 5 (200B) | Rcvd: 1 (46B) | Lost: 4 (80.00%)| Echoed: 0 (0B)
Tx time: 4.00504s | Tx bytes/s: 49.94 | Tx pkts/s: 1.25
Rx time: 5.00618s | Rx bytes/s: 9.19 | Rx pkts/s: 0.20
Nping done: 1 IP address pinged in 6.39 seconds
</screen>
</example>
<para>
In this example, the output is a bit more tricky. The absence of error
messages shows that the Echo client has successfully established an Echo
session with the server. However, no CAPT packets can be seen in the output.
This means that none of the transmitted packets reached the server.
Interestingly, a TCP SYN-ACK packet was received in response to the first
TCP-SYN packet (and also, it is known that the target host does not have
port 80 open). This behavior reveals the presence of a transparent web proxy
cache server (which in this case is an old MS ISA server).
</para>
</refsect1>
<!-- TIMING AND PERFORMANCE OPTIONS **************************************** -->
<refsect1 id="nping-man-timing-performance-options">
<title>Timing and Performance Options</title>
<variablelist>
<varlistentry>
<term>
<option>--delay <replaceable>time</replaceable></option> (Delay between probes)
<indexterm significance="preferred"><primary><option>--delay</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option lets you control for how long will Nping wait before
sending the next probe. Like in many other ping tools, the default
delay is one second.
<replaceable>time</replaceable> must be a positive
integer or floating point number. By default it is specified in
seconds, however you can give an explicit unit by appending
<literal>ms</literal> for milliseconds, <literal>s</literal> for seconds,
<literal>m</literal> for minutes, or <literal>h</literal> for hours
(e.g. <literal>2.5s</literal>, <literal>45m</literal>, <literal>2h</literal>).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--rate <replaceable>rate</replaceable></option> (Send probes at a given rate)
<indexterm significance="preferred"><primary><option>--rate</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option specifies the number of probes that Nping should send
per second. This option and <option>--delay</option> are inverses;
<option>--rate 20</option> is the same as
<option>--delay 0.05</option>. If both options are used, only the
last one in the parameter list counts.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<!-- MISCELLANEOUS OPTIONS ************************************************ -->
<refsect1 id="nping-man-miscellaneous-options">
<title>Miscellaneous Options</title>
<variablelist>
<varlistentry>
<term><option>-h</option>,
<option>--help</option> (Display help)
<indexterm significance="preferred"><primary><option>--help</option> (Nping option)</primary></indexterm>
<indexterm significance="preferred"><primary><option>--h</option> (Nping option)</primary><see><option>--help</option></see></indexterm>
</term>
<listitem>
<para>
Displays help information and exits.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-V</option>,
<option>--version</option> (Display version)
<indexterm significance="preferred"><primary><option>--version</option> (Nping option)</primary></indexterm>
<indexterm significance="preferred"><primary><option>-V</option> (Nping option)</primary><see><option>--version</option></see></indexterm>
</term>
<listitem>
<para>
Displays the program's version number and quits.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-c <replaceable>rounds</replaceable></option>,
<option>--count <replaceable>rounds</replaceable></option> (Stop after a given number of rounds)
<indexterm significance="preferred"><primary><option>--count</option> (Nping option)</primary></indexterm>
<indexterm significance="preferred"><primary><option>-c</option> (Nping option)</primary><see><option>--count</option></see></indexterm>
</term>
<listitem>
<para>
This option lets you specify the number of times that Nping should
loop over target hosts (and in some cases target ports). Nping calls
these <quote>rounds</quote>. In a basic execution with only one target (and only
one target port in TCP/UDP modes), the number of rounds matches the
number of probes sent to the target host. However, in more complex
executions where Nping is run against multiple targets and multiple
ports, the number of rounds is the number of times that Nping sends
a complete set of probes that covers all target IPs and all
target ports. For example, if Nping is asked to send TCP SYN packets
to hosts 192.168.1.0-255 and ports 80 and 433, then 256&thinsp;&times;&thinsp;2&nbsp;=&nbsp;512 packets
are sent in one round. So if you specify <option>-c 100</option>, Nping will
loop over the different target hosts and ports 100 times, sending
a total of 256&thinsp;&times;&thinsp;2&thinsp;&times;&thinsp;100&nbsp;=&nbsp;51200 packets. By default Nping runs for
5 rounds. If a value of 0 is specified, Nping will run continuously.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-e <replaceable>name</replaceable></option>,
<option>--interface <replaceable>name</replaceable></option> (Set the network interface to be used)
<indexterm significance="preferred"><primary><option>--interface</option> (Nping option)</primary></indexterm>
<indexterm significance="preferred"><primary><option>-e</option> (Nping option)</primary><see><option>--interface</option></see></indexterm>
</term>
<listitem>
<para>
This option tells Nping what interface should be used to send and
receive packets. Nping should be able to detect this automatically,
but it will tell you if it cannot. <replaceable>name</replaceable>
must be the name of an existing network interface with an assigned
IP address.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--privileged</option> (Assume that the user is fully privileged)
<indexterm significance="preferred"><primary><option>--privileged</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
Tells Nping to simply assume that it is privileged enough to perform
raw socket sends, packet sniffing, and similar operations that
usually require special privileges. By default Nping quits if such
operations are requested by a user that has no root or administrator
privileges. This option may be useful on Linux, BSD or similar
systems that can be configured to allow unprivileged users to perform
raw-packet transmissions. The
<envar>NPING_PRIVILEGED</envar><indexterm><primary><envar>NPING_PRIVILEGED</envar> environment variable</primary></indexterm>
environment variable
may be set as an alternative to using <option>--privileged</option>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--unprivileged</option> (Assume that the user lacks raw socket privileges)
<indexterm significance="preferred"><primary><option>--unprivileged</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
This option is the opposite of <option>--privileged</option>. It tells Nping to treat
the user as lacking network raw socket and sniffing privileges.
This is useful for testing, debugging, or when the raw network
functionality of your operating system is somehow broken. The
<envar>NPING_UNPRIVILEGED</envar><indexterm><primary><envar>NPING_UNPRIVILEGED</envar> environment variable</primary></indexterm>
environment variable may be set as an
alternative to using <option>--unprivileged</option>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--send-eth</option> (Use raw ethernet sending)
<indexterm significance="preferred"><primary><option>--send-eth</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
Asks Nping to send packets at the raw ethernet (data link) layer
rather than the higher IP (network) layer. By default, Nping chooses
the one which is generally best for the platform it is running on.
Raw sockets (IP layer) are generally most efficient for Unix
machines, while ethernet frames are required for Windows operation
since Microsoft disabled raw socket support. Nping still uses raw IP
packets despite this option when there is no other choice (such as
non-ethernet connections).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--send-ip</option> (Send at raw IP level)
<indexterm significance="preferred"><primary><option>--send-ip</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
Asks Nping to send packets via raw IP sockets rather than sending
lower level ethernet frames. It is the complement to the
<option>--send-eth</option> option.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--bpf-filter <replaceable>filter spec</replaceable></option>
<option>--filter <replaceable>filter spec</replaceable></option> (Set custom BPF filter)
<indexterm significance="preferred"><primary><option>--bpf-filter</option> (Nping option)</primary></indexterm>
<indexterm significance="preferred"><primary><option>--filter</option> (Nping option)</primary><see>--bpf-filter</see></indexterm>
</term>
<listitem>
<para>
This option lets you use a custom BPF filter. By default Nping
chooses a filter that is intended to capture most common responses
to the particular probes that are sent. For example, when sending
TCP packets, the filter is set to capture packets whose destination
port matches the probe's source port or ICMP error messages that may
be generated by the target or any intermediate device as a result of
the probe. If for some reason you expect strange packets in response
to sent probes or you just want to sniff a particular kind of
traffic, you can specify a custom filter using the BPF syntax used
by tools like
tcpdump.<indexterm><primary>tcpdump</primary></indexterm>
See the documentation at <ulink url="http://www.tcpdump.org/"/> for
more information.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-H</option>,
<option>--hide-sent</option> (Do not display sent packets)
<indexterm significance="preferred"><primary><option>--hide-sent</option> (Nping option)</primary></indexterm>
<indexterm significance="preferred"><primary><option>-H</option> (Nping option)</primary><see>--hide-sent</see></indexterm>
</term>
<listitem>
<para>
This option tells Nping not to print information about sent packets.
This can be useful when using very short inter-probe delays (i.e.,
when flooding), because printing information to the standard
output has a computational cost and disabling it can probably
speed things up a bit. Also, it may be useful when using Nping to
detect active hosts or open ports (e.g. sending probes to all TCP
ports in a /24 subnet). In that case, users may not want to see
thousands of sent probes but just the replies generated by active
hosts.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-N</option>,
<option>--no-capture</option> (Do not attempt to capture replies)
<indexterm significance="preferred"><primary><option>--no-capture</option> (Nping option)</primary></indexterm>
<indexterm significance="preferred"><primary><option>-N</option> (Nping option)</primary><see><option>--no-capture</option></see></indexterm>
</term>
<listitem>
<para>
This option tells Nping to skip packet capture. This means that
packets in response to sent probes will not be processed or
displayed. This can be useful when doing flooding and network stack
stress tests. Note that when this option is specified, most of
the statistics shown at the end of the execution will be useless.
This option does not work with TCP Connect mode.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<!-- OUTPUT OPTIONS **************************************** -->
<refsect1 id="nping-man-output-options">
<title>Output Options</title>
<variablelist>
<varlistentry>
<term>
<option>-v<optional><replaceable>level</replaceable></optional></option>,
<option>--verbose <optional><replaceable>level</replaceable></optional></option> (Increase or set verbosity level)
<indexterm significance="preferred"><primary><option>--verbose</option> (Nping option)</primary></indexterm>
<indexterm significance="preferred"><primary><option>-v</option> (Nping option)</primary><see><option>--verbose</option></see></indexterm>
</term>
<listitem>
<para>
Increases the verbosity level, causing Nping to print more
information during its execution. There are 9 levels of verbosity
(-4 to 4). Every instance of <option>-v</option> increments the verbosity level by one
(from its default value, level 0). Every instance of option <option>-q</option>
decrements the verbosity level by one. Alternatively you can specify
the level directly, as in <option>-v3</option> or
<option>-v-1</option>. These are the available levels:
</para>
<indexterm><primary>verbosity levels of Nping</primary></indexterm>
<variablelist>
<varlistentry>
<term>Level -4</term>
<listitem>
<para>
No output at all. In some circumstances you may not want
Nping to produce any output (like when one of your work mates is
watching over your shoulder). In that case level -4 can be useful
because although you won't see any response packets, probes will
still be sent.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Level -3</term>
<listitem>
<para>
Like level -4 but displays fatal error messages so you can
actually see if Nping is running or it failed due to some error.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Level -2</term>
<listitem>
<para>
Like level -3 but also displays warnings and recoverable errors.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Level -1</term>
<listitem>
<para>
Displays traditional run-time information (version, start time,
statistics, etc.) but does not display sent or received packets.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Level 0</term>
<listitem>
<para>
This is the default verbosity level. It behaves like level -1 but
also displays sent and received packets and some other important information.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Level 1</term>
<listitem>
<para>
Like level 0 but it displays detailed information about
timing, flags, protocol details, etc.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Level 2</term>
<listitem>
<para>
Like level 1 but displays very detailed information
about sent and received packets and other interesting information.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Level 3</term>
<listitem>
<para>
Like level 2 but also displays the raw hexadecimal dump of sent
and received packets.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Level 4 and higher</term>
<listitem>
<para>
Same as level 3.
</para>
</listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-q<optional><replaceable>level</replaceable></optional></option>,
<option>--reduce-verbosity <optional><replaceable>level</replaceable></optional></option> (Decrease verbosity level)
<indexterm significance="preferred"><primary><option>--reduce-verbosity</option> (Nping option)</primary></indexterm>
<indexterm significance="preferred"><primary><option>-q</option> (Nping option)</primary><see>--reduce-verbosity</see></indexterm>
</term>
<listitem>
<para>
Decreases the verbosity level, causing Nping to print less
information during its execution.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-d<optional><replaceable>level</replaceable></optional></option> (Increase or set debugging level)
<indexterm significance="preferred"><primary><option>-d</option> (Nping option)</primary></indexterm>
</term>
<listitem>
<para>
When even verbose mode doesn't provide sufficient data for you,
debugging is available to flood you with much more! As with the
<option>-v</option>, debugging is enabled with a command-line
flag <option>-d</option> and the debug level can be increased by
specifying it multiple times. There are 7 debugging levels (0 to 6).
Every instance of <option>-d</option> increments debugging level by
one. Provide an argument to <option>-d</option> to set the level
directly; for example <option>-d4</option>.
</para>
<para>
Debugging output is useful when you suspect a bug in Nping, or if
you are simply confused as to what Nping is doing and why. As this
feature is mostly intended for developers, debug lines aren't
always self-explanatory. You may get something like
<indexterm><primary>Nsock</primary><secondary>debug output of</secondary></indexterm>
<screen>
NSOCK (1.0000s) Callback: TIMER SUCCESS for EID 12; tcpconnect_event_handler<continuation/>(): Received callback of type TIMER with status SUCCESS
</screen>
If you don't understand a line, your only
recourses are to ignore it, look it up in the source code, or
request help from the development list (<citetitle>nmap-dev</citetitle>). Some lines are
self-explanatory, but the messages become more obscure as the debug
level is increased. These are the available levels:
</para>
<indexterm><primary>debug levels of Nping</primary></indexterm>
<variablelist>
<varlistentry>
<term>Level 0</term>
<listitem>
<para>
Level 0. No debug information at all. This is the default level.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Level 1</term>
<listitem>
<para>
In this level, only very important or high-level debug information
will be printed.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Level 2</term>
<listitem>
<para>
Like level 1 but also displays important or medium-level debug
information
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Level 3</term>
<listitem>
<para>
Like level 2 but also displays regular and low-level debug information.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Level 4</term>
<listitem>
<para>
Like level 3 but also displays messages only a real Nping freak would
want to see.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Level 5</term>
<listitem>
<para>
Like level 4 but it enables basic debug information related to
external libraries like Nsock.<indexterm><primary>Nsock</primary></indexterm>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Level 6</term>
<listitem>
<para>
Like level 5 but it enables full, very detailed, debug information
related to external libraries like Nsock.
</para>
</listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id="nping-man-bugs">
<title>Bugs</title>
<indexterm><primary>bugs, reporting</primary></indexterm>
<para>Like its author, Nping isn't perfect. But you can help make
it better by sending bug reports or even writing patches. If Nping
doesn't behave the way you expect, first upgrade to the latest Nmap
version available from <ulink url="https://nmap.org/download.html"/>. If
the problem persists, do some research to determine whether it has already
been discovered and addressed. Try searching for the error message on our
search page at <ulink url="http://insecure.org/search.html"/> or at Google.
Also try browsing the <citetitle>nmap-dev</citetitle> archives at
<ulink url="http://seclists.org/"/><indexterm>
<primary><citetitle>nmap-dev</citetitle> mailing list</primary></indexterm>
Read this full manual page as
well. If nothing comes out of this, mail a bug report to
<email>dev@nmap.org</email>. Please include everything
you have learned about the problem, as well as what version of
Nping you are running and what operating system version it is
running on. Problem reports and Nping usage questions sent to
<email>dev@nmap.org</email> are far more likely to be answered than
those sent to Fyodor directly. If you subscribe to the nmap-dev
list before posting, your message will bypass moderation and get
through more quickly. Subscribe at
<ulink url="https://nmap.org/mailman/listinfo/dev"/>.</para>
<para>Code patches to fix bugs are even better than bug reports.
Basic instructions for creating patch files with your changes are
available at <ulink url="https://svn.nmap.org/nmap/HACKING"/>. Patches may
be sent to <citetitle>nmap-dev</citetitle> (recommended) or to any of the
authors listed in the next section directly.</para>
</refsect1>
<refsect1 id="nping-man-author">
<title>Authors</title>
<para>Luis MartinGarcia <email>luis.mgarc@gmail.com</email> (<ulink url="http://www.luismg.com" />)</para>
<para>Fyodor <email>fyodor@nmap.org</email> (<ulink url="http://insecure.org" />)</para>
</refsect1>
</refentry>
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