[openib-general] Same IP address on multiple net devices and routing

[Roland Dreier]

    Hal> Hi, Does anyone know what the Linux routing code does in
    Hal> terms of selecting an outgoing interface when multiple net
    Hal> devices have been configured with the same IP address ?

It follows the routing table.  If you assign the same local IP address
to multiple interfaces then you have to be careful to set up routing
so that your traffic goes to the right place.

In fact you can think of Linux networking as attaching IP addresses to
the system as a whole instead of a particular interface, because for
example by default Linux will respond to ARP queries on any
interface.  Assigning addresses to a particular interface is just a
hint for how the kernel sets up routes by default.

 - R.