Two Gateways on Ubuntu, Split access.

I set my Ubuntu server with to private gateways, which had access too two public ip addresses. I wanted to receive requests to the web tomcat and apache servers from both networks. This is how I configured my split access on my server to have traffic come in through both private subnets and sent out through the ip that it came in on.

#!/bin/sh

# split access

# http://lartc.org/howto/lartc.rpdb.multiple-links.html#AEN268

# http://tldp.org/HOWTO/Adv-Routing-HOWTO/lartc.rpdb.multiple-links.html

# GoneVertical.org

# 1. One creates two additional routing tables, say T1 and T2. These are added in /etc/iproute2/rt_tables. Then you set up routing in these tables as follows:

# echo 1 T1 >> /etc/iproute2/rt_tables

# echo 2 T2 >> /etc/iproute2/rt_tables

# interface

IF0=lo

IF1=eth0

IF2=eth1

# ips

IP1=192.168.12.100

IP2=192.168.10.100

# gateways

P1=192.168.12.1

P2=192.168.10.1

# ip network

P0_NET=0.0.0.0

P1_NET=192.168.12.0

P2_NET=192.168.10.0

#echo $IF0 $IF1 $IF2

#echo $IP1 $IP2

#echo $P0_NET $P1_NET $P2_NET

# create routing tables

ip route add $P1_NET dev $IF1 src $IP1 table T1

ip route add default via $P1 table T1

ip route add $P2_NET dev $IF2 src $IP2 table T2

ip route add default via $P2 table T2

# create routing for local requests

# not sure if i need this

#ip route add $P0_NET dev $IF0 table T1

#ip route add $P2_NET dev $IF2 table T1

#ip route add 127.0.0.0/8 dev lo table T1

#ip route add $P0_NET dev $IF0 table T2

#ip route add $P1_NET dev $IF1 table T2

#ip route add 127.0.0.0/8 dev lo table T2

# main routing table

ip route add $P1_NET dev $IF1 src $IP1

ip route add $P2_NET dev $IF2 src $IP2

# default route preference

ip route add default via $P1

# routing rules

ip rule add from $IP1 table T1

ip rule add from $IP2 table T2