On Wed, Nov 09, 2005 at 08:57:45PM -0500, Adam Rosi-Kessel wrote: > I'm troubeshooting an issue of accessing a VPN through NAT. Right now the > problem can be reduced to the following question: > > Under what conditions would inbound packets not be routing through the nat > PREROUTING chain? That's a problem that puzzles me too. Do you have fancy routing tables? (several different tables setup w/ iproute2). I also have a setup in which icmp packets will not get to PREROUTING. My understanding is that the kernel does not understand they are destined for that box: could that be your situation? In my stup, ifconfig eth3: eth3 Link encap:Ethernet HWaddr 00:0A:5E:59:EF:09 inet addr:192.168.111.1 Bcast:192.168.111.255 Mask:255.255.255.0 but these packets 10:18:07.676131 IP 192.168.111.1 > 217.27.90.70: icmp 64: echo request seq 213 10:18:07.726977 IP 217.27.90.70 > 192.168.111.1: icmp 64: echo reply seq 213 do not enter PREROUTING and are just discarded In my case this is due to a peculiar routing tables setup, http://mailman.ds9a.nl/pipermail/lartc/2005q4/017168.html that I have not been able to debug: I didn't receice any hint on this list, lartc and netdev. Is it such an obscure matter? sandro -- Sandro Dentella *:-) e-mail: sandro@xxxxxxxx http://www.tksql.org TkSQL Home page - My GPL work