Subject: Network Problems after Running Tcpdump
To: None <firstname.lastname@example.org>
From: Seth Kurtzberg <email@example.com>
Date: 10/07/2001 02:05:48
I am seeing a strange problem that occurs frequently after running tcpdump.
The machine exhibiting the problem is part of a firewall, and thus is
forwarding packets, using ipf, ipnat, and running some proprietary proxy
After running tcpdump, the machine becomes unreachable over the net. It
doesn't respond to ping requests, doesn't route packets, and just generally
appears dead with respect to networking. This is true for both interfaces.
Most of the time, if I get on the machine (using the console) and ping its
neighbors, it recovers; perhaps the routing tables are repopulated by the
pings? If the pings don't make it work, it is necessary to stop and restart
the routing daemon. Thus far stopping and restarting the routing daemon has
I'm thinking that perhaps the way I shut tcpdump down is related to the
problem. (I've been using control-c at a shell prompt in an xterm.) I tried
shutting down tcpdump using kill -15, but this did not change the behavior
(that is, the routing problems still appear after running tcpdump).
I've not seen this problem running tcpdump in other environments (Solaris,
Thanks in advance. Also, thanks for some earlier pointers about installing
software with the package system. It worked flawlessly.
Machine Independent Software
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