From mboxrd@z Thu Jan 1 00:00:00 1970 From: Raphael Benedet Date: Thu, 19 Feb 2004 16:48:23 +0000 Subject: Re: [LARTC] 2 providers & DNAT: incoming packets not forwarded Message-Id: <4034E8D7.5030808@raph.com> List-Id: References: <4034CBF2.50104@raph.com> In-Reply-To: <4034CBF2.50104@raph.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lartc@vger.kernel.org Hi, It is of course set to 1. I already have DNATing on eth1 and it works very well. I suppose my problem come from my routing table but I don't understand why no route is found to 172.16.1.4 coming from ppp0 with the current configuration. Regards, Raph Alexander A. Naumov wrote: > Hi! > May be you need to set /proc/sys/net/ipv4/ip_forward sysctl value to 1? > > Best regards, > Alexander A. Naumov > > On Thu, Feb 19, 2004 at 03:45:06PM +0100, Raphael Benedet wrote: > >>Hi, >> >>I have a problem with incoming connections on my Linux gateway. >>I have 2 providers, cable modem on eth1 and dsl on eth2 <-> ppp0 >>(pppoe). The lan network is connected to eth0. At the moment, I have a >>very simple configuration where the default route is via eth1 (cable >>modem). I set up DNAT on ppp0 to forward incoming traffic for certain >>ports to a computer behind the gateway/firewall: >>iptables -t nat -A PREROUTING -i ppp0 -p tcp -m tcp --dport 2000 -j DNAT >>--to-destination 172.16.1.4 >>Packets get lost and never reach the FORWARD chain (I logged all packets >>to be sure) >> >>Here are my routes: >> >># ip route ls >>215.136.169.1 dev ppp0 proto kernel scope link src 215.136.169.15 >>135.165.199.128/25 dev eth1 proto kernel scope link src 135.165.199.139 >>172.16.0.0/16 dev eth0 proto kernel scope link src 172.16.1.1 >>default via 135.165.199.129 dev eth1 >> >>So, I understand traffic by default goes via eth1, but why don't >>incoming packets redirected (DNATed) to an intranet IP address go out >>via eth0? >>If I change my default route in table main to go via ppp0, then, it >>works. And DNATing on eth1 works with the current configuration. >> >>I don't have any other routing tables nor complex routing rules: >># ip rule ls >>0: from all lookup local >>32766: from all lookup main >>32767: from all lookup default >> >>I am running kernel 2.4.23 with Julian's patches. >> >>Any help would be greatly appreciated. Thank you. >> >>Raph >> >> >>-- >> >>Raphael Benedet >>3D Artists - raph.com >>"bringing art into the third dimension" >> >>_______________________________________________ >>LARTC mailing list / LARTC@mailman.ds9a.nl >>http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/ > > > _______________________________________________ LARTC mailing list / LARTC@mailman.ds9a.nl http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/