From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Haxby Subject: REDIRECT problem Date: Thu, 15 Jul 2010 10:34:18 +0100 Message-ID: <4C3ED61A.4050303@oracle.com> 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"; format="flowed" To: netfilter@vger.kernel.org Hello All, For some time now, I've been using REDIRECT (roughly) like this: $IPT -t nat -A PREROUTING -j proxyt $IPT -t nat -A proxyt -d -p tcp -m tcp -k RETURN (repeated lots of times for different networks) $IPT -t nat -A proxyt -p tcp -m tcp ! --dport 3128 -j REDIRECT --to-ports 3128 That works just fine: TCP connections to any network other than the specific get directed to the process listening on port 3128 (which then uses HTTP CONNECT on a proxy to connect to the Big Bad Internet). I use ebtables on a pair of machines running Xen to redirect traffic to this machine: +-------------+ +-------------+ | xen | | xen | | +---+ | | +---+ | | +---+ | P |=========| P'| +---+ | | | A | +-+-+ | | +---+ | B | | | +---+ | | | +---+ | | | | | | +---------|---+ +-------------+ | Big Bad Internet Traffic from A is redirected (by ebtables) to P which has these rules on it and that connection is just fine. Traffic from B is directed to P' which then forwards traffic to P over a private network and until recently that worked just fine. Previously, P was running Fedora 11 with the 2.6.30.10-105.2.16.fc11 kernel; but now its running Fedora13 with the 2.6.33.6-147.fc13. So, previously on B I could connect to (say) google.com:80 and traffic was redirect to the process listing on port 3128 via P' and the private link and everything was fine. Now, unfortunately, the same connection from B is hits the REDIRECT rule but the process listening on port 3128 doesn't come out of the accept(2) syscall. The same connection from A does work. The only visible difference is that traffic from A appears to come into P from eth0 and traffic from B appears to come from eth1. Inserting a LOG target immediately before the REDIRECT rule shows the packet hitting that REDIRECT (and one immediately after doesn't show anything so the REDIRECT is definitely matching). Something seems to have changed between 2.6.30 and 2.6.33 and I'm at a loss to know what. I've looked around a bit, but so far haven't found anything. Hopefully someone listening will be able to say "oh, you need to do " :-) Or that this should never have worked in the first place because of something horrible I was relying on. jch