I found very good article on load balancing at http://www.diegolima.org/wordpress/?p=36.. I could not implement it though as my requirement is slightly different from pure load balancing.
We have two ISP connections. I have connected both these routers to Linux server on eth0 (public ip 121.XXX.XX.XXX) and eth1(192.168.129.XXX) respectively, and our internal network is on eth2 (192.168.1.XXX).
I have decided that that our FTP should use eth1 interface, Squid should use eth0, Sendmail should use eth0 and some users should use eth0 and some other user should use eth1.
Can anybody tell if it is possible, how can I achieve this using iptables and iproute2? Step by step help is highly appreciated. Thanks in advance.