In article <199812020444.XAA06678@ginger.cmf.nrl.navy.mil>,
	Ken Hornstein <kenh@cmf.nrl.navy.mil> writes:
> I just tried this, and it seems to work:
> 
> - Create a UDP socket
> - bind() it to a local port

This step is unnecessary ...

> - connect() it to the "supplied IP address"
> - getsockname() on the socket

... but otherwise it works perfect. Here is the diff for "traceroute":

Index: traceroute.c
===================================================================
RCS file: /cvsroot/src/usr.sbin/traceroute/traceroute.c,v
retrieving revision 1.25
diff -u -r1.25 traceroute.c
--- traceroute.c	1998/08/27 20:31:02	1.25
+++ traceroute.c	1998/12/07 02:31:58
@@ -730,9 +730,36 @@
 		 */
 		setsin(from, al->addr);
 		if (n > 1 && device == NULL) {
-			Fprintf(stderr,
-		    "%s: Warning: Multiple interfaces found; using %s @ %s\n",
-			    prog, inet_ntoa(from->sin_addr), al->device);
+			int sock;
+			struct sockaddr_in help;
+			int help_len;
+
+			sock = socket(AF_INET, SOCK_DGRAM, 0);
+			if (sock < 0) {
+				Fprintf(stderr, "%s: udp socket: %s\n", prog, strerror(errno));
+				exit(1);
+			}
+			help.sin_family = AF_INET;
+			/*
+			 * At this point the port number doesn't matter,
+			 * it only has to be greater zero.
+			 */
+			help.sin_port = 42;
+			help.sin_addr.s_addr = to->sin_addr.s_addr;
+			if (connect(sock, (struct sockaddr *)&help, sizeof(help)) < 0) {
+				Fprintf(stderr, "%s: connect: %s\n", prog, strerror(errno));
+				(void)close(sock);
+				exit(1);
+			}
+			help_len = sizeof(help);
+			if (getsockname(sock, (struct sockaddr *)&help, &help_len) < 0 ||
+			    help_len != sizeof(help)) {
+				Fprintf(stderr, "%s: getsockname: %s\n", prog, strerror(errno));
+				(void)close(sock);
+				exit(1);
+			}
+			setsin(from, help.sin_addr.s_addr);
+			(void)close(sock);
 		}
 	} else {
 		hi = gethostinfo(source);

That should fix PR bin/4427.

-- 
Matthias Scheler                                http://home.owl.de/~tron/