diff --git a/docs/refguide.xml b/docs/refguide.xml
index 6f6586395..5bdba4e4a 100644
--- a/docs/refguide.xml
+++ b/docs/refguide.xml
@@ -657,12 +657,11 @@ you would expect.</para>
           takes the same format as with the port lists in the
           previously discussed TCP and UDP host discovery options.  If
           no protocols are specified, the default is to send multiple
-          IP packets for ICMP (protocol 1), IGMP (protocol 2), TCP
-          (protocol 6) and UDP (protocol 17).  The default protocols
-          can be configured at compile-time by changing
-          DEFAULT_PROTO_PROBE_PORTS in <filename>nmap.h</filename>.
-          Note that for the ICMP, IGMP, TCP and UDP protocols, the
-          packets are sent with the additional headers while other
+          IP packets for ICMP (protocol 1), IGMP (protocol 2), and
+          IP-in-IP (protocol 4).  The default protocols can be
+          configured at compile-time by changing DEFAULT_PROTO_PROBE_PORTS
+          in <filename>nmap.h</filename>.  Note that for the ICMP and IGMP,
+          the packets are sent with the additional headers while other
           protocols are sent with no additional data beyond the IP
           header (unless the <option>--data-length</option> option is
           specified).</para>
diff --git a/nmap.h b/nmap.h
index ee11a8143..924c0a887 100644
--- a/nmap.h
+++ b/nmap.h
@@ -277,8 +277,8 @@ void *realloc();
 				      to 113 */
 #define DEFAULT_UDP_PROBE_PORT 31338 /* The port UDP probes (esp. "ping" probes) go to if unspecified
 				     by user */
-#define DEFAULT_PROTO_PROBE_PORTS { 1, 2, 6, 17 } /* The IPProto ping probes to use if unspecified
-						     by user */
+#define DEFAULT_PROTO_PROBE_PORTS { 1, 2, 4 } /* The IPProto ping probes to use if unspecified
+						 by user */
 
 #define MAX_DECOYS 128 /* How many decoys are allowed? */