Index: nmap.cc
===================================================================
--- nmap.cc	(revision 32862)
+++ nmap.cc	(working copy)
@@ -303,6 +303,7 @@
          "  -g/--source-port <portnum>: Use given port number\n"
          "  --proxies <url1,[url2],...>: Relay connections through HTTP/SOCKS4 proxies\n"
          "  --data-length <num>: Append random data to sent packets\n"
+         "  --comment <string>: Append a comment string to sent packets\n"
          "  --ip-options <options>: Send packets with specified ip options\n"
          "  --ttl <val>: Set IP time-to-live field\n"
          "  --spoof-mac <mac address/prefix/vendor name>: Spoof your MAC address\n"
@@ -584,6 +585,7 @@
     {"version-trace", no_argument, 0, 0}, /* Display -sV related activity */
     {"data_length", required_argument, 0, 0},
     {"data-length", required_argument, 0, 0},
+    {"comment", required_argument, 0, 0},
     {"send_eth", no_argument, 0, 0},
     {"send-eth", no_argument, 0, 0},
     {"send_ip", no_argument, 0, 0},
@@ -824,6 +826,14 @@
             error("WARNING: Payloads bigger than 1400 bytes may not be sent successfully.");
           o.extra_payload = (char *) safe_malloc(MAX(o.extra_payload_length, 1));
           get_random_bytes(o.extra_payload, o.extra_payload_length);
+        } else if (optcmp(long_options[option_index].name, "comment") == 0) {
+          o.extra_payload_length = strlen(optarg);
+          if (o.extra_payload_length < 0 || o.extra_payload_length > MAX_PAYLOAD_ALLOWED)
+            fatal("comment length must be between 0 and %d", MAX_PAYLOAD_ALLOWED);
+          if (o.extra_payload_length > 1400) /* 1500 - IP with opts - TCP with opts. */
+            error("WARNING: Payloads bigger than 1400 bytes may not be sent successfully.");
+          o.extra_payload = (char *) safe_malloc(MAX(o.extra_payload_length, 1));
+          strcpy(o.extra_payload, optarg);
         } else if (optcmp(long_options[option_index].name, "send-eth") == 0) {
           o.sendpref = PACKET_SEND_ETH_STRONG;
         } else if (optcmp(long_options[option_index].name, "send-ip") == 0) {