Scott Silva wrote:
> I have had this problem on and off since RedHat 6, and I always worked through
> it, but I thought I would ask.
> When you have multiple network interfaces, how does the system determine the
> default route?
> Or is it the first, (or last) interface that comes up?
>
> On the problem systems I have to add a "route add default..." statement in
> some systems in the rc.local to get them to work right.
>
>
>
You can add a default route into /etc/sysconfig/network, and the network
with the matching network ip will take the route.
If you have more that one default route capability on different
interfaces, you can set up routing tables for each of the networks , and
then apply a weighting to each network default route in the main routing
table...
There is an excellent discussion on it here, that answers your later
question about sending out packets on the right interface.
http://lartc.org/howto/lartc.rpdb.multiple-links.html
If you follow the guidlines in this document but only add a default
route to your main preferred gateway all traffic outgoing will be routed
to that gateway but replies topackets on the other interfaces will still
be serviced via the default routes on those interfaces if they come from
networks outside the network ranges of all the network interfaces on the
box....
If you want more detail, send me your ip ranges and ips and I will send
you a set of ip rules/routes to achieve what you want...
Regards
Pete
