Subject: Strange packet redirection
To: None <>
From: Rick Byers <>
List: current-users
Date: 05/20/1999 13:51:09

I've got a NetBSD-1.4 machine doing for my local network (192.168.149.*)
over my cable modem.  I have a WEIRD situation where the gateway machine
is redirecting packets to itself when it should just be translating the
source address.

For example, if (from my PC at I telnet to,
it establishes a connetion with the gateway machine instead!  tcpdump on
the internal network shows what I would expect, but the gateway machine
never sends the packets out, it just handles them itself.  This has
happened with a few other (seemingly random, but I didn't look hard)
destination IP addresses.  If I clear ALL NAT rules and flush the NAT
table, this still happens.  There is no output from 'ipmon -a' indicating
that a NAT rule was applied or anything. This didn't happen under
NetBSD-1.3.3 (even with ipfilter-3.2.10 installed).  There are no
entries in the routing table that would apply to the requested destination
address either (except for the default route).

Any idea what might cause this?  Might it have something to do with the
"fix changing of IP destination address in ip_natin()" change in ipfilter
3.2.10p1?  Is there a reason this patch was never integrated into NetBSD's


Rick Byers                       University of Waterloo, Computer Science