Multiple IP Binding and Source IP Address

Murdock1979 · 07-02-2012, 05:51 AM

Hello All,

When an application binds to multiple IP addresses, how does Linux choose the source IP address when responding to a request?

Does it only depend on the routing table (by choosing the IP associated with the outgoing NIC), or is there some other mechanism for choosing the source IP?

Thanks

acid_kewpie · 07-02-2012, 05:58 AM

at the OS level it's the interface it's leaving.

Murdock1979 · 07-02-2012, 06:15 AM

Hello,

However, I've seen that using ip route, one can specify the outgoing routing according the original incoming packet, as described here:
http://lartc.org/howto/lartc.rpdb.multiple-links.html

If that is so, then the binding is not only using the routing table for choosing a source IP, but also chooses it according to the original packet it is responding to, but how?

Thanks