[ILUG] Routing.

[Paul Jakma]

On 16 Jan 2002, Mark Kilmartin wrote:

> Chapter 4 of the Adv-Routing-HOWTO seems to maybe cover this.
> 
> Or at least it seemed to make some sense to me after much looking at it.
> 
> I think you would set up route so that if the source was the IP address
> of the external interface then route to that interface.

you can do that certainly. here's an edited version of the route setup 
on a machine here:

[root at florence alphyra]# ip ru ls
0:      from all lookup local
32763:  from 172.16.0.0/12 lookup main internal
32764:  from 10.0.0.0/8 lookup main internal
32765:  from 192.168.0.0/24 lookup main internal  
32759:  from all to isp1/29 lookup main isp1-pa 
32760:  from all to isp2/29 lookup main isp2-pa
32761:  from isp1/29 lookup isp1 isp1
32762:  from isp2/29 lookup isp2 isp2
32766:  from all lookup main 
32767:  from all lookup 253
[root at florence alphyra]# ip ro li table isp1
default via isp1-gw dev eth1  metric 1 
[root at florence alphyra]# ip ro li table isp2
default via isp2-gw dev eth1  metric 1

however, that will lead to most of your stuff only using one 1 isp. 
cause most of your applications packets will have source address set 
to one IP *AFAICT*.

nat on the routers is much simpler.. cause you dont have to play the 
above games.

--paulj