From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steve Hill Subject: Conntrackd entries timing out Date: Thu, 24 Nov 2011 17:29:54 +0000 Message-ID: <4ECE7F12.6080004@opendium.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 I'm configuring conntrackd to support an active/active pair of firewalls. I would like to keep them as synchronised as possible so am setting it up with FTFW mode and "DisableExternalCache On". I'm monitoring the connection tracker records on both hosts with "conntrack -L". If I send a single ping to something from firewall A, I correctly see the conntrack entry appear for that on both firewalls. Since the I only sent 1 ping, I see the timer on both ticking down from 30 seconds, after which the entry disappears from both firewalls - this bit seems fine. The problem I'm having is if I start a continuous ping from firewall A, sending 1 packet per second, I again see the conntrack entry appear on both firewalls as expected. However, whilst firewall A shows the timer sat at 30 seconds since it is regularly being reset by each packet, firewall B's connection again ticks down and is then removed. So now, the conntrack tables are unsynchronised - firewall A is still seeing the pings and keeps the conntrack entry alive whilst firewall B has removed the entry. If I turn the external cache on and monitor it with "conntrackd -e", it appears to behave correctly - the entry stays in the external cache so long as it it in firewall A's conntrack table. The only way I've found of keeping these machines correctly synchronised with the external cache disabled is to run "conntrackd -n" every few seconds on both hosts to force a resynchronisation, which does appear to reset the timers correctly. So I'm hoping someone is able to answer these questions: 1. Is this a bug or is there something I'm missing about the way it is expected to work? 2. Is running "conntrackd -n" on both machines every few seconds a safe and feasible workaround, or am I asking for trouble? Thanks. -- - Steve Hill Technical Director Opendium Limited http://www.opendium.com Direct contacts: Instant messager: xmpp:steve@opendium.com Email: steve@opendium.com Phone: sip:steve@opendium.com Sales / enquiries contacts: Email: sales@opendium.com Phone: +44-844-9791439 / sip:sales@opendium.com Support contacts: Email: support@opendium.com Phone: +44-844-4844916 / sip:support@opendium.com