From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guido Trentalancia Subject: Port forwarding with iptables on tunnel interface Date: Thu, 11 Feb 2010 19:14:54 +0100 Message-ID: <1265912094.2985.44.camel@tesla.lan> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: Sender: netfilter-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: netfilter@vger.kernel.org Hello ! I have the following problem. I need to forward/redirect all connections to port 25 (smtp) from one host (192.168.3.64) to another host on the same network (192.168.3.69). I am using the following iptables rules: -A PREROUTING -p tcp --dport 25 -j DNAT --to-destination 192.168.3.69 -A POSTROUTING -p tcp -d 192.168.1.65 --dport 25 -j MASQUERADE and I have also tried the following alternative rules: -A PREROUTING -p tcp --dport 25 -j DNAT --to-destination 192.168.3.69 -A POSTROUTING -p tcp -d 192.168.1.65 --dport 25 -j SNAT --to-source 192.168.3.64 The connections come from an IP-IP tunnel and they are allowed by the following iptables rules: -A INPUT -p 4 -i eth0 -j ACCEPT -A OUTPUT -p 4 -o eth0 -j ACCEPT It used to work until a few days ago. But now it only works from within the LAN and not from the tunnel. I have not changed any iptables rules and I have only upgraded the system to the latest kernel (2.6.32.8). The version of iptables that I am using is 1.4.3.1. Any idea on how to get it back working ? Regards, Guido