Question

I have a linux machine Iam using as a router with multible interfaces and multible internet connection
say eth0–isp1

eth1--isp2

eth2--isp3

the gateway is eth0 throw isp1

and eth3–local1 10.0.0.x

eth4--local2 192.168.1.x

i need local1 ip 192.168.1.10 to go throw isp3, eth2

thanks

Answer 1

You need to use policy routing for this. You create a new routing table and use it when the source IP is 192.168.1.10.

ip route add ... table $TABLENUM                  # your usual routes, for the new table
...
ip route add default via $ISP3 table $TABLENUM    # gateway for the new table
ip rule add from 192.168.1.10/32 lookup $TABLENUM # use the new table for this IP
ip rule add to 192.168.1.10/32 lookup $TABLENUM   # make it symmetric, for clarity