Hi, My Debian box has 2 network cards, eth0 connected to my ADSL modem and eth1 to my local LAN via a hub. I have been using iptables / NAT to get the local LAN on the 'net for a couple of years now with great success. Unfortunately I fried a hard drive and had to start from scratch so thought I would use the newest Debian release. That's when my problems began. The box is reliable and NIC's are stable before any iptables rules are applied. I know this because I am driving it through an SSH session on eth1 and using aptitude to get some quite large files of the 'net (kernel-source etc.). When I apply iptables rules for NAT etc I get the classic MTU problem where I can't load some webpages etc. Part of the problem is I don't know how to set MTU any more! There is no more pppoe.conf file and it seems the the kernel based pppd / pppoe plugin and the roaring penguin one are configured using different methods. How do I know which one I have? How do I find out how to configure MTU etc? I tried setting it in dsl-provider but it has no impact on the MTU shown for ppp0. I have also used the iptables TCPMSS clamp but the result remains the same. More troubling again is that after a while I get NETDEV WATCHDOG transmit timeout errors that eventuate in the box hanging totally. This only happens after I have run my iptables script though! I have tried installing a 2.4.27 kernel and a 2.4.25 kernel I compiled myself (to get rid of APIC) and get the same symptoms. I am obviously missing something very basic! Can anybody shed any light on this? Thanks in advance Chris
