From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jeff Largent <jlargent@imagelinks.com>
Subject: Re: Gateway Switch script
Date: Thu, 28 Aug 2003 08:36:33 -0400
Sender: linux-admin-owner@vger.kernel.org
Message-ID: <3F4DF751.5000407@imagelinks.com>
References: <1062066265.19990.19.camel@krishna.softprosys.com>
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To: Murali Potla <murali.potla@softprosys.com>
Cc: linux-admin <linux-admin@vger.kernel.org>

You could use something like this, run out of cron.

#!/bin/bash

$DEF='192.168.1.1'
$BACK='192.168.2.1'
$CURRENT=`netstat -rn | grep "^0.0.0.0" | awk '{print $2}'`

# if $DEF is current check and switch to backup if down
if [ $CURRENT = $DEF ]; then
   ping -c1 -w5 $DEF

   if [ $? > 0 ]; then
     route del default gw $DEF
     route add default gw $BACK
   fi
# else check the backup and switch to def if down
else
   ping -c1 -w $BACK

   if [ $? > 0 ]; then
     route del default gw $BACK
     route add default gw $DEF
   fi
fi

This is totally untested so you milage may vary.





Murali Potla wrote:
> Hi,
> 
> Does any body has a script to automatically switch the default gateway
> between two IPs. ?
> 
> I have two ISP connections. I want to switch between them when one is
> down 
> 
> 
> Regards
> Murali
>  
> 
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> 

-- 
Jeff Largent                   ImageLinks, Inc.