I have been trying to implement load balance and fail over on a linux machine having multiple interfaces.
Currently I am using two ISP lines and I wish to split the network traffic such that both of them are used. For this I have made changes to the IP tables and the rules that apply to them.
Following is the Linux Advances Routing and Traffic Control (LARTC) link I am referring http://lartc.org/howto/lartc.rpdb.multiple-links.html
Connections do get distributed on both ISP lines. However, it is observed that once a connection is routed over a particular interace, it follows the same route each time.
This is because of the entry that gets made in the routing cache. Load balancing is severely affected due to this phenomenon. I have been clearing the cache at regular intervals which has not made the situation any better.