How to configure a Linux Router to consist two default gw ?

[kennyen]

hi,

I have a question hope jim or and visitor here can guide me to the solution !
the question is:
i have two adsl lease line connected to two router and then connect to a subnet.
lease line1 lease line2
__l__ __l__
l l l l
l_LR1_l l_LR2_l
l l
__l___________________l____192.168.0.0 network

if i connect my network as shown at diagram above,
every client pc inside 192.168.0.0/24 network can configure there default gateway to LR1 or LR2 (nic) ip address depends on which lease line they want to use.right? (each linux router consist 2 ethernet card)
__________________________________________________ __
and now,

lease line1 lease line2
l l
l l
l____ ____l
eth0_l__l_eth1
l l
l LR l
l_____l
leth2
___l____ 192.168.0.0/24 network

if i configure my network as shown at above, can i choose some 192.168.0.0/24's subnet use lease line1 and some subnet use lease line2 without change the client pc default gateway? and so that i can save a linux router. (linux router here consist 3 ethernet card).

let assume, i have seubnet 192.168.0.0/27 and 192.168.0.32/27 now i want subnet 192.168.0.0/27 use lease line 1 and 192.168.0.32/27 use lease line 2. all network stated here are connectted to a D-Link (DES 1024R) 10/100 Fast/Ethernet switch. how can i do that or which external program can perform this function?

i'm using Redhat 7.3 (valhalla).

thanks

kennyen

[JimH]

Yes it is possible to route by source address. There isn't much documentation out there about these features of the linux kernel and what there is could be improved.

I read some of this howto a couple of months ago.

http://www.tldp.org/HOWTO/Adv-Routing-HOWTO.html

Take a look at sections 3 & 4. It doesn't really go into a lot of depth and there are not many examples, but you can get a idea of how it works.

Jim H

[kennyen]

thanks JimH,

finally, i got what i needed.

thanks a lot.
from
kennyen