Trunk backup via second NIC

I have asterisk 1.8 installed on Dell server with 2 network interfaces (eth0 and eth1),

Eth0 is connected to ISP aaa
Eth1 is connected to ISP bbb

A SIP trunk is configured and working well on the default interface (eth0, via ISP aaa)

is there a way to make eth1 as an automatic backup for the SIP trunk in case of ISP aaa is down (to register and make calls via ISP bbb)??

Test the hangup cause, and if it suggests a network problem, repeat the dial via the other ITSP.

Note that configuratons where there are multiple, disjoint, networks seem to cause problems, although Asterisk does try to work out the interface address to use in SIP headers.

thanks for your reply, but my problem is how to force a second SIP trunk to use the second ITSP (via the second interface)?

Configure a route to their address via the interface. That is is an OS configuration issue, basically the same as configuring routes to non-local subnets on your LAN.

good idea, thank you :smile: