Index: netcat-1.10/netcat.c
===================================================================
--- netcat-1.10.orig/netcat.c	2007-09-17 22:04:23.000000000 +0200
+++ netcat-1.10/netcat.c	2007-09-17 22:40:48.000000000 +0200
@@ -86,6 +86,9 @@
 #include <unistd.h>
 #endif
 
+/* quick hack to make it working without patched kernel source */
+#define IP_TRANSPARENT 19
+
 /* handy stuff: */
 #define SA struct sockaddr	/* socket overgeneralization braindeath */
 #define SAI struct sockaddr_in	/* ... whoever came up with this model */
@@ -179,6 +182,7 @@
 USHORT o_zero = 0;
 int o_quit = -1; /* 0 == quit-now; >0 == quit after o_quit seconds */
 int o_keepalive = 0;
+int o_transparent = 0;
 #ifdef IP_TOS
 unsigned char o_tos = 0;
 #endif
@@ -689,6 +693,13 @@
       holler("nnetfd set keepalive failed");
     }
   }
+  if (o_transparent) {
+    x = 1;
+    rr = setsockopt(nnetfd, SOL_IP, IP_TRANSPARENT, &x, sizeof(x));
+    if (rr == -1) {
+      holler("nnetfd set transparent failed");
+    }
+  }
 #if 0
 /* If you want to screw with RCVBUF/SNDBUF, do it here.  Liudvikas Bukys at
    Rochester sent this example, which would involve YET MORE options and is
@@ -1508,7 +1519,7 @@
 
 /* If your shitbox doesn't have getopt, step into the nineties already. */
 /* optarg, optind = next-argv-component [i.e. flag arg]; optopt = last-char */
-  while ((x = getopt (argc, argv, "abc:e:g:G:hi:klno:p:q:rs:tuvw:x:z")) != EOF) {
+  while ((x = getopt (argc, argv, "abc:e:g:G:hi:klno:p:q:rs:tTuvw:x:z")) != EOF) {
 /* Debug (("in go: x now %c, optarg %x optind %d", x, optarg, optind)) */
     switch (x) {
       case 'a':
@@ -1557,6 +1568,8 @@
 	break;
     case 'k':
         o_keepalive = 1; break;
+      case 'T':
+        o_transparent = 1; break;
       case 'l':				/* listen mode */
 	o_listen++; break;
       case 'n':				/* numeric-only, no DNS lookups */
@@ -1822,6 +1835,7 @@
 	-t			answer TELNET negotiation");
 #endif
   holler ("\
+	-T			set IP_TRANSPARENT for the socket\n\
 	-u			UDP mode\n\
 	-v			verbose [use twice to be more verbose]\n\
 	-w secs			timeout for connects and final net reads");