From mboxrd@z Thu Jan 1 00:00:00 1970 From: "sufcrusher" Date: Thu, 11 Mar 2004 11:29:04 +0000 Subject: Re: [LARTC] script to perform dead gateway detection Message-Id: <004201c4075c$0f3f9f70$3366640a@p951> List-Id: References: <008c01c40710$b81b6210$0100a8c0@newlife> In-Reply-To: <008c01c40710$b81b6210$0100a8c0@newlife> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lartc@vger.kernel.org Try using the -I option for ping, this forces it to use a certain interface: ping -I ${MY_IP_1} -c 1 ${GATEWAY_1} You can also add a route to the gateway to force it to use that interface. I do the same for the 2 SMTP servers of the different ISP's. I can't connect to one SMTP server from the other ISP anyway, so better make it impossible altogether. sufcrusher ----- Original Message ----- From: "Ming-Ching Tiew" To: Sent: Thursday, March 11, 2004 3:29 AM Subject: [LARTC] script to perform dead gateway detection > > 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/