Trixbox / Asterisk on 2 Network Card

I want to have asterisk / Trixbox running on 2 network cards as i am using 2 different ISP to route my calls. I was told this is something to do with the routing table within Linux itself and not asterisk. My config is as follows calls comes in from SIP if calls prefix is 1. it goes to eth0 if calls prefix is 011. it goes to eth1 Thank You ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform OS : CentOS