From mboxrd@z Thu Jan 1 00:00:00 1970 From: Denis Fedorishenko Date: Thu, 11 Mar 2004 07:39:11 +0000 Subject: Re[2]: [LARTC] script to perform dead gateway detection Message-Id: <277287922.20040311093911@nuclearcat.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lartc@vger.kernel.org Hello Daniel, Thursday, March 11, 2004, 4:55:15 AM, you wrote: Maybe better just to use ping -t 2 anyhost :) DC> How about iptables -A OUTPUT --destination ${GATEWAY_1} -j TTL --set-ttl DC> 2 (or 1, I'm not sure if the ttl dec is done at all with output chains) DC> So, after the next hop, if the IP address isn't GATEWAY_1, then the DC> packet is dead in the water. DC> Ming-Ching Tiew wrote: >> I am also having some difficulty in doing dead gateway >> detection using a shell script :- >> >> Basically I am using ping -c 1 ${GATEWAY_1} If it times >> out, I supposed it got into error, so it is probably time for me to >> change route. >> >> However, even if the ping comes back, it does not mean the >> GATEWAY is alive as my nexthop; this is because I figured >> that the packet could have made a U-turn via the one of the alive >> links to come back to answer the ping request, ie the gateway is >> alive for a packet on the external network, but the gateway >> is still down from inside point of view, and this can happen >> due to a faulty connection between by second link IP and the >> second link gateway ! >> >> Without patching the kernel to do dead gateway detection, >> how do I find out if a particular gateway is dead as my >> NEXTHOP ? >> >> >> >> >> >> >> _______________________________________________ >> LARTC mailing list / LARTC@mailman.ds9a.nl >> http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: >> http://lartc.org/ DC> _______________________________________________ DC> LARTC mailing list / LARTC@mailman.ds9a.nl DC> http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/ -- Best regards, Denis mailto:nuclearcat@nuclearcat.com _______________________________________________ LARTC mailing list / LARTC@mailman.ds9a.nl http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/