From owner-freebsd-hackers Fri Dec 30 13:36:33 1994 Return-Path: hackers-owner Received: (from root@localhost) by freefall.cdrom.com (8.6.9/8.6.6) id NAA01205 for hackers-outgoing; Fri, 30 Dec 1994 13:36:33 -0800 Received: from seine.zytek.fr (seine.zytek.fr [193.104.118.2]) by freefall.cdrom.com (8.6.9/8.6.6) with ESMTP id NAA01197 for ; Fri, 30 Dec 1994 13:35:56 -0800 Received: (from melvin@localhost) by seine.zytek.fr (8.6.8/8.6.6) id WAA02083; Fri, 30 Dec 1994 22:36:55 +0100 Date: Fri, 30 Dec 1994 22:36:55 +0100 From: Stephen Melvin Message-Id: <199412302136.WAA02083@seine.zytek.fr> To: freebsd-hackers@freebsd.org Subject: source IP address mangled on certain packets!!?? Sender: hackers-owner@freebsd.org Precedence: bulk I recently upgraded to 1.1.5.1R and I'm having a rather strange problem with packets from "ping" and "traceroute". The setup is as follows. I have a dialup-PPP connection which is periodically established with pppd and then disconnected with kill -INT. Most of this happens automatically and it has been working great for the last 3 months. Now, after I upgraded I noticed that somtimes (but not every time) pppd is invoked, certain (but not all) outgoing packets get sent with garbage in the source IP address field (consequently, they never return). However, packets from most applications work all the time. I don't know if the problem is with the new pppd or the new kernel, but it doesn't seem to be with ping itself as the same thing happens with the 1.1R version of ping. Interestingly, I can ping the address on the other end of the ppp link OK. Here is a sample output from "tcpdump" for three different commands. "ping 193.107.193.22" (this one is correct) ------- 09:30:36.947118 193.104.118.2 > 193.107.193.22: icmp: echo request 09:30:37.260806 193.107.193.22 > 193.104.118.2: icmp: echo reply 09:30:37.950530 193.104.118.2 > 193.107.193.22: icmp: echo request 09:30:38.264977 193.107.193.22 > 193.104.118.2: icmp: echo reply 09:30:38.960544 193.104.118.2 > 193.107.193.22: icmp: echo request 09:30:39.273976 193.107.193.22 > 193.104.118.2: icmp: echo reply ------- "ping 193.107.193.17" (where the heck did 86.0.26.0 come from?) ------- 09:26:38.520605 86.0.26.0 > 193.107.193.17: icmp: echo request 09:26:39.533073 86.0.26.0 > 193.107.193.17: icmp: echo request 09:26:40.543428 86.0.26.0 > 193.107.193.17: icmp: echo request ------- "traceroute 193.107.193.17" (whoa, these are not IP numbers!!) ------- 09:21:50.003290 65.0.128.0.33881 > 193.107.193.17.33435: udp 12 [ttl 1] 09:21:55.013135 149.0.21.0.33881 > 193.107.193.17.33436: udp 12 [ttl 1] 09:22:00.022998 44.0.173.1.33881 > 193.107.193.17.33437: udp 12 [ttl 1] 09:22:05.033429 0.0.0.0.33881 > 193.107.193.17.33438: udp 12 09:22:10.043181 76.0.128.0.33881 > 193.107.193.17.33439: udp 12 09:22:15.052946 67.0.7.0.33881 > 193.107.193.17.33440: udp 12 ------- So, to summarize: 1. problem doesn't occur with 1.1R kernel, pppd and ping. 2. problem does occur with 1.1R ping on 1.1.5.1R kernel and pppd. 3. problem doesn't occur all the time, but it seems to either always occur or never occur for a given invocation of pppd and once it starts, I have to reboot to fix it. 4. problem seems to be only with outgoing packets from ping and traceroute. (Note: incoming echo request packets from a remote destination get bounced back properly). 5. outgoing packets to the machine on the other end of the ppp link work OK all the time. -------------- Stephen Melvin melvin@zytek.fr ---------------