From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Beekhof Subject: Re: Masquerade difficulties Date: Sat, 8 Jan 2005 11:03:22 +0100 Message-ID: <26ef5e7050108020312386f9c@mail.gmail.com> References: <20050107221238.GA10943@pog.tecnopolis.ca> Reply-To: Andrew Beekhof Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20050107221238.GA10943@pog.tecnopolis.ca> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: netfilter-bounces@lists.netfilter.org Errors-To: netfilter-bounces@lists.netfilter.org Content-Type: text/plain; charset="us-ascii" To: Trevor Cordes Cc: netfilter@lists.netfilter.org On Fri, 7 Jan 2005 16:12:38 -0600, Trevor Cordes wrote: > > I'm having some difficulties getting masquerading to work and hoping > > for some pointers... > > I can try to help. But you'll need to better describe your network > layout. Can you draw a little diagram showing where A, B & C are? Sure, A & B are connected directly to a netgear DSL modem/hub. C is part of my company's network which I'm accessing over the internet with ipsec. I've also tried replacing C with google.com (after specifying an appropriate routing rule) with no success. Does that clear things up? > > Are you sure that BoxC doesn't have some firewall on (XP SP2) that is > eating the ping packets? XP? God no! All the machines are linux boxes running either SLES9 or Gentoo :) No firewall on B or C. >From what I can tell, the packets from BoxB are getting lost on BoxA. I just tried using telnet and tcpdump and although I get logs like this: Jan 8 08:35:55 BoxA IN=eth0 OUT=eth0 SRC=192.168.9.22 DST=10.10.2.86 LEN=60 TOS=0x10 PREC=0x00 TTL=63 ID=48952 DF PROTO=TCP SPT=34452 DPT=69 WINDOW=3840 RES=0x00 SYN URGP=0 ... the packets never actually arrive at BoxC (10.10.2.86). I dont think they ever leave BoxA but I'm not sure I understand the tcpdump output enough to say for sure. A dump of my iptables in case it helps... mayo linux # iptables -L -t nat Chain PREROUTING (policy ACCEPT) target prot opt source destination Chain POSTROUTING (policy ACCEPT) target prot opt source destination LOG all -- anywhere anywhere LOG level warning MASQUERADE all -- anywhere anywhere Chain OUTPUT (policy ACCEPT) target prot opt source destination mayo linux # iptables -L -t filter Chain INPUT (policy ACCEPT) target prot opt source destination Chain FORWARD (policy ACCEPT) target prot opt source destination Chain OUTPUT (policy ACCEPT) target prot opt source destination mayo linux # iptables -L -t mangle Chain PREROUTING (policy ACCEPT) target prot opt source destination Chain INPUT (policy ACCEPT) target prot opt source destination Chain FORWARD (policy ACCEPT) target prot opt source destination LOG all -- anywhere anywhere LOG level debug Chain OUTPUT (policy ACCEPT) target prot opt source destination Chain POSTROUTING (policy ACCEPT) target prot opt source destination