Load Balancing (2 ISP 1 Connection) Configuration using Ubuntu

This is an example router configuration for you who want to use 2 ISP in 1 connection applied to your local network.

1. Insert Ubuntu disc
2. Boot
3. Install a command line system
4. $ sudo passwd root
5. # su -

# vi /etc/network/interfaces
auto eth0
iface eth0 inet static
address 10.0.148.48
netmask 255.255.255.0auto eth1
iface eth1 inet static
address 192.168.0.222
netmask 255.255.255.0auto eth2
iface eth2 inet static
address 192.168.1.222
netmask 255.255.255.0# vi /etc/apt/source-list
deb ftp://192.168.0.1/pub/edgy-repo1/ edgy main restricted
deb ftp://192.168.0.1/pub/edgy-repo2/ edgy universe
deb ftp://192.168.0.1/pub/edgy-repo3/ edgy universe
deb ftp://192.168.0.1/pub/edgy-repo4/ edgy universe multiverse
# apt-get update

# apt-get install openssh-server
# /etc/init.d/ssh restart

# vi /etc/timezone
Asia/Jakarta

---------- iproute2 ------------------------------------------------

/sbin/ip link set lo up
/sbin/ip link set eth0 up
/sbin/ip link set eth1 up
/sbin/ip link set eth2 up

/sbin/ip route flush table adsl
/sbin/ip route flush table rtrwnet
/sbin/ip route flush table internet

/sbin/ip addr add 127.0.0.1/8 brd 127.0.0.255 dev lo

/sbin/ip addr add 192.168.1.222/24 brd 192.168.1.255 dev eth2
# /sbin/ip addr add 10.0.148.48/24 brd 10.0.148.255 dev eth0
/sbin/ip addr add 192.168.0.222/24 brd 192.168.0.255 dev eth1

/sbin/ip route add 127.0.0.0/8 dev lo
/sbin/ip route add 10.5.148.0/24 via 10.0.148.254 dev eth0
/sbin/ip route add 192.168.0.0/24 dev eth1
/sbin/ip route add 44.132.33.0/24 via 192.168.0.10 dev eth1
/sbin/ip route add 192.168.11.0/24 via 192.168.0.10 dev eth1
/sbin/ip route add 125.160.6.0/24 via 192.168.1.1 dev eth2
/sbin/ip route add 202.159.32.0/24 via 192.168.1.1 dev eth2

/sbin/ip rule add prio 10 table main
/sbin/ip rule add prio 20 table adsl
/sbin/ip rule add prio 30 table rtrwnet
/sbin/ip rule add prio 40 table internet

/sbin/ip route del default table main
/sbin/ip route del default table adsl
/sbin/ip route del default table rtrwnet
/sbin/ip route del default table internet

/sbin/ip rule add prio 20 from 192.168.1.0/24 table adsl
/sbin/ip route add default via 192.168.1.1 dev eth2 src 192.168.1.222 proto static table adsl
/sbin/ip route append prohibit default table adsl metric 1 proto static

/sbin/ip rule add prio 30 from 10.0.148.0/24 table rtrwnet
/sbin/ip route add default via 10.0.148.254 dev eth0 src 10.0.148.48 proto static table rtrwnet
/sbin/ip route append prohibit default table rtrwnet metric 5 proto static

# Set up load balancing gateways
/sbin/ip rule add prio 40 table internet
/sbin/ip route add default proto static table internet \
nexthop via 192.168.1.1 dev eth2 weight 1 \
nexthop via 10.0.148.254 dev eth0 weight 10

# Setup routing to ISPs
/sbin/ip route add 202.138.236.0/24 proto static table internet \
nexthop via 192.168.1.1 dev eth2 weight 10 \
nexthop via 10.0.148.254 dev eth0 weight 1

----------- iptables -----------------------------------------------

/bin/echo 1 > /proc/sys/net/ipv4/ip_forward

/sbin/iptables -F
/sbin/iptables -P INPUT DROP
/sbin/iptables -A INPUT -p tcp -i eth1 --destination-port 25 -s ! 192.168.0.1 -j DROP

/sbin/iptables -A INPUT -i eth1 -j ACCEPT
/sbin/iptables -A INPUT -i eth0 -p tcp -s 0/0 --dport 25 -j ACCEPT
/sbin/iptables -A INPUT -i eth2 -p tcp -s 0/0 --dport 25 -j ACCEPT
/sbin/iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
/sbin/iptables -A INPUT -p tcp -i eth0 -j REJECT --reject-with tcp-reset
/sbin/iptables -A INPUT -p tcp -i eth2 -j REJECT --reject-with tcp-reset
/sbin/iptables -A INPUT -p udp -i eth0 -j REJECT --reject-with icmp-port-unreachable
/sbin/iptables -A INPUT -p udp -i eth2 -j REJECT --reject-with icmp-port-unreachable

/sbin/iptables -t nat -A POSTROUTING -o eth2 -j SNAT --to 192.168.1.222
/sbin/iptables -t nat -A POSTROUTING -o eth0 -j SNAT --to 10.0.148.48

----------- /etc/iproute2/rt_tables --------------------------------

120 adsl
121 rtrwnet
123 internet


Install Router in Ubuntu
By: Onno W. Purbo