From mboxrd@z Thu Jan  1 00:00:00 1970
From: Patrick McHardy <kaber@trash.net>
Subject: Re: SIP NAT CONTRACK Module with Netfilter in kernel 2.4.x
Date: Sat, 04 Mar 2006 10:04:53 +0100
Message-ID: <44095835.7010703@trash.net>
References: <cb81d4010603020310x1f865d2dhf14088682952108@mail.gmail.com>
	<cb81d4010603020312q3309cd70w27fd5862744eb09f@mail.gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Cc: netfilter-devel@lists.netfilter.org
Return-path: <netfilter-devel-bounces@lists.netfilter.org>
To: Huy Vu Pham <markoflinux@gmail.com>
In-Reply-To: <cb81d4010603020312q3309cd70w27fd5862744eb09f@mail.gmail.com>
List-Unsubscribe: <https://lists.netfilter.org/mailman/listinfo/netfilter-devel>,
	<mailto:netfilter-devel-request@lists.netfilter.org?subject=unsubscribe>
List-Archive: </pipermail/netfilter-devel>
List-Post: <mailto:netfilter-devel@lists.netfilter.org>
List-Help: <mailto:netfilter-devel-request@lists.netfilter.org?subject=help>
List-Subscribe: <https://lists.netfilter.org/mailman/listinfo/netfilter-devel>,
	<mailto:netfilter-devel-request@lists.netfilter.org?subject=subscribe>
Sender: netfilter-devel-bounces@lists.netfilter.org
Errors-To: netfilter-devel-bounces@lists.netfilter.org
List-Id: netfilter-devel.vger.kernel.org

Huy Vu Pham wrote:
> Dear Netfilter Devel list,
> I got problem very strange with Netfilter in linux kernel 2.4.x.
> 
> I apply contrack/nat SIP protocol
> (http://openwrt.alphacore.net/patches/buildroot/317-netfilter-nat-sip
> )  with HELPER module to capture all RTP packets.
> (
> #Out from WAN site: eth1
> iptables -t mangle -A POSTROUTING -o eth1 -p UDP -m helper --helper
> sipd00 -j MARK --set-mark 0x20
> #Out from LAN site: eth0
> iptables -t mangle -A POSTROUTING -o eth0 -p UDP -m helper --helper
> sipd00 -j MARK --set-mark 0x21
> )
> 
> My test case like this:
> SIP PHONE A (Outside NAT) ----- NAT BOX (Have SIP ALG) ------- SIP
> PHONE B (Inside NAT).
> 
> 1. Reboot NAT BOX, A call B. SIP MODULE can capture all RTP packets,
> Before RTP timeout, I make the call from B to A also OK.
> 
> 2. Reboot NAT BOX, B call A. SIP MODULE "CAN NOT" capture any RTP packets.
> Before RTP timeout, I make the call from A to B also got the same problem.
> 
> What is difference between case (1) and case(2)?

The SIP helper currently only tracks one direction. I wanted to fix
it for some time, but didn't get to it yet.