diff --git a/docs/refguide.xml b/docs/refguide.xml index b1c89e317..bdadb07b8 100644 --- a/docs/refguide.xml +++ b/docs/refguide.xml @@ -327,6 +327,107 @@ you would expect. # and extend to the end of the line. + + + + (No DNS resolution) + + + + + reverse DNSdisabling with + Tells Nmap to never do reverse DNS + resolution on the active IP addresses it finds. Since + DNS can be slow even with Nmap's built-in parallel stub + resolver, this option can slash scanning times. + + + + + + (DNS resolution for all targets) + + + + Tells Nmap to + always do reverse DNS + resolution on the target IP addresses. Normally reverse DNS is + only performed against responsive (online) hosts. + + + + + + (Scan each resolved address) + + + + If a hostname target resolves to more than one address, scan + all of them. The default behavior is to only scan the first + resolved address. Regardless, only addresses in the appropriate + address family will be scanned: IPv4 by default, IPv6 with + . + + + + + + + (Use system DNS resolver) + + + + + By default, Nmap reverse-resolves IP addresses by sending + queries directly to the name servers configured on your host + and then listening for responses. Many requests (often + dozens) are performed in parallel to improve performance. + Specify this option to use your system resolver instead (one + IP at a time via the getnameinfo call). This is slower + and rarely useful unless you find a bug in the Nmap parallel + resolver (please let us know if you do). The system + resolver is always used for forward lookups (getting an IP address from a hostname). + + + + + + + (Servers to use for reverse DNS queries) + + + + + By default, Nmap determines your DNS servers + (for rDNS resolution) from your resolv.conf file (Unix) or + the Registry (Win32). Alternatively, you may use this + option to specify alternate servers. This option is not + honored if you are using . + Using multiple DNS servers is often faster, + especially if you choose authoritative servers for your + target IP space. This option can also improve stealth, as + your requests can be bounced off just about any recursive + DNS server on the Internet. + + This option also comes in handy when scanning private + networks. Sometimes only a few name servers provide + proper rDNS information, and you may not even know where + they are. You can scan the network for port 53 (perhaps + with version detection), then try Nmap list scans + () specifying each name server one at a + time with until you find one + which works. + + This option might not be honored if the DNS response + exceeds the size of a UDP packet. In such a situation our DNS + resolver will make the best effort to extract a response from the + truncated packet, and if not successful it will fall back to + using the system resolver. Also, responses that contain CNAME aliases + will fall back to the system resolver. + + + @@ -908,107 +1009,6 @@ Traceroute works by sending packets with a low TTL (time-to-live) in an attempt - - - - (No DNS resolution) - - - - - reverse DNSdisabling with - Tells Nmap to never do reverse DNS - resolution on the active IP addresses it finds. Since - DNS can be slow even with Nmap's built-in parallel stub - resolver, this option can slash scanning times. - - - - - - (DNS resolution for all targets) - - - - Tells Nmap to - always do reverse DNS - resolution on the target IP addresses. Normally reverse DNS is - only performed against responsive (online) hosts. - - - - - - (Scan each resolved address) - - - - If a hostname target resolves to more than one address, scan - all of them. The default behavior is to only scan the first - resolved address. Regardless, only addresses in the appropriate - address family will be scanned: IPv4 by default, IPv6 with - . - - - - - - - (Use system DNS resolver) - - - - - By default, Nmap reverse-resolves IP addresses by sending - queries directly to the name servers configured on your host - and then listening for responses. Many requests (often - dozens) are performed in parallel to improve performance. - Specify this option to use your system resolver instead (one - IP at a time via the getnameinfo call). This is slower - and rarely useful unless you find a bug in the Nmap parallel - resolver (please let us know if you do). The system - resolver is always used for forward lookups (getting an IP address from a hostname). - - - - - - - (Servers to use for reverse DNS queries) - - - - - By default, Nmap determines your DNS servers - (for rDNS resolution) from your resolv.conf file (Unix) or - the Registry (Win32). Alternatively, you may use this - option to specify alternate servers. This option is not - honored if you are using . - Using multiple DNS servers is often faster, - especially if you choose authoritative servers for your - target IP space. This option can also improve stealth, as - your requests can be bounced off just about any recursive - DNS server on the Internet. - - This option also comes in handy when scanning private - networks. Sometimes only a few name servers provide - proper rDNS information, and you may not even know where - they are. You can scan the network for port 53 (perhaps - with version detection), then try Nmap list scans - () specifying each name server one at a - time with until you find one - which works. - - This option might not be honored if the DNS response - exceeds the size of a UDP packet. In such a situation our DNS - resolver will make the best effort to extract a response from the - truncated packet, and if not successful it will fall back to - using the system resolver. Also, responses that contain CNAME aliases - will fall back to the system resolver. - - -