====== Loosing Gateway on freebsd 5.5 ======

I have not seen any solution so far, so following custom scripts will help you.

add following line to rc.local.
<code bash | /etc/rc.local>
/usr/local/bin/netmonitor
</code>

create script netmonitor
<code bash | /usr/local/bin/netmonitor>
#!/bin/sh

. /etc/rc.conf

netmonitor(){
   while [ 1 ]; do
      ping -c 5 -t 1 $defaultrouter

      if [ $? -ne 0 ]; then
         sh /etc/netstart
         sh /etc/rc.virtual
      fi
      sleep 5
   done
}

netmonitor &
</code>

==== OR ====

Following script you should run from the crontab.

<code bash | gatewayping.sh>
#!/usr/local/bin/bash

gtway=24.24.222.25
ping -c 5 -t 1 $gtway
      if [ $? -ne 0 ]; then
         sh /etc/netstart
         sh /etc/rc.virtual
         echo "$date Gateway issue Detected" >> /var/log/messages
      fi
</code>