I converted a Fedora 13 system as multiple uplink router using the steps mentioned at lartc.org with 1 LAN (eth0) and load balance with two WAN(eth1, eth2).

Now the problem is,
we have an application which is connecting to its server on internet at every 5 minutes. so when application first connected to the server it connected through eth1 which can be seen from ip route show cache command.
As kernel automatically flushes the routing cache after some time, when the application tried to connect, it went through eth2 as load balance is ON. When the application goes through eth2 it is not able to connect to the server.

What could be the possible reasons for this behavior? and what will be the solution for it?

Thanks in advance.