Load Balancer / Multi-WAN - Gateway wont change [workaround]

xibalba

Hey Everyone on the board,
I looked around here quite a bit, read the multi-wan documentation on the wiki/docs areas but still was unable to get it working.
First let me explain what I was trying to accomplish. I wanted a CARP router solution with Failover to WAN2 only if WAN1 was down. I did not want to load balance these connections because one was a T3 and the other a T1. After many failed attempts I finally just setup 1 load balancer pool with both my gateways.
I set it up as follows

Type: Gateway
Behaviour: Failover
Monitor IP #1 : WAN 1 Gateway
Interface #1 : WAN
Monitor IP #2 : WAN 2 Gateway
Interface #2 : WAN2

Then I just used the script outlined below. This script still needs a-lot of work, like another to check that it is still running, heartbeat, etc… If someone wants to add-on to it that would be great.

#!/usr/local/bin/php -f

01/18/2008 Copyright Reza Ambler reza@rndcomputing.com# All rights reserved.

while(true)
{
check_gateways();
sleep(2);
}

function check_gateways()
{
// lb is the name of the load balancer pool that
// has the gateways for wan1 and wan2 in it
// line #1 in this pool file is the currently working gateway

$working_gw = exec ( "head -n 1 /tmp/lb.pool" ) ;

// figure out the current default gateway

exec("netstat -nr -f inet", $routes);
$routes = implode("\n", $routes);

if (preg_match("/^default\s+([\d.]+)/m", $routes, $gateway) == 1) {
$current_gw = $gateway[1];
}

// if working_gw is not equal, to the current default gateway
// in netstat then we know the current default gw is down
// proceed to switch the default gw and flush the states

if ($working_gw == $gateway[1])
{
echo "State unchanged\n";
}
else
{
//change gw, clear states
echo "NOTICE: Changing route to $working_gw\n";
echo "NOTICE: Clearing state tables\n";
exec("route change default $working_gw");
exec("pfctl -F state");
}
}
?>

Please let me know your thoughts. If you think it needs major modification, let me know I have only had brief time to test it but it did seem to work.

I forgot to add that I put this file in /usr/local/bin/mon-gw, set chmod 755 /usr/local/bin/mon-gw, and executed it./reza@rndcomputing.com