internet-sharing-and-load-balancing

HOW TO LOAD BALANCING BETWEEN TO ISP PROVIDER IN LINUX

First of all make sure that your server or pc have connected three lan cables

1. Live IP1
2. Live IP2
3. Local Lan

Find out the following information before you proceed with the rest of the guide:

1. IP address of external interfaces (interfaces connected to your modems). This is not the gateway address.
2. Gateway IP address of each broadband connections. This is the first hop gateway, could be your DSL modem IP address if it has been configured as the gateway following the tip below.
3. Name, IP address & netmask of external interfaces like eth1, eth2 etc. My external interfaces are eth1 & eth2.
4. Relative weights you want to assign to each connection. My Tata connection is 4 times faster than BSNL connection. So I assign the weight of 4 to Tata and 1 to BSNL. You must use low positive integer values for weights. For same connection speeds weights of 1 & 1 are appropriate. The weights determine how the load is balanced across multiple connections. In my case Tata is 4 times as likely to be used as route for a particular site in comparison with BSNL.

How to setup default load balancing for multiple ADSL / Cable connections

#IP address of external interfaces. This is not the gateway address.

IP1=192.168.1.10

IP2=192.168.0.10

#Gateway IP addresses. This is the first (hop) gateway, could be your router IP

#address if it has been configured as the gateway

GW1=192.168.1.1

GW2=192.168.0.1

# Relative weights of routes. Keep this to a low integer value. I am using 4

# for TATA connection because it is 4 times faster

W1=1

W2=4

# Broadband providers name; use your own names here.

NAME1=bsnl

NAME2=tata

You must change the example below to use your own IP addresses and other details. Even with that inconvenience a real example is much easier to understand than examples with complex notations. The example given below is copy-pasted from our intranet configuration. It works perfectly as advertised.

First you need to create two (or more) routes in the routing table ( /etc/iproute2/rt_tables ). Open the file and make changes similar to what is show below. I added the following for my two connections:

1 bsnl

2 tata

To add a default load balancing route for our outgoing traffic using our dual internet connections (ADSL broadband connections from BSNL & Tata Indicom) here are the lines I included in rc.local file:

ip route add 192.168.1.0/24 dev eth1 src 192.168.1.10 table bsnl

ip route add default via 192.168.1.1 table bsnl

ip route add 192.168.0.0/24 dev eth2 src 192.168.0.10 table tata

ip route add default via 192.168.0.1 table tata

ip rule add from 192.168.1.10 table bsnl

ip rule add from 192.168.0.10 table tata

ip route add default scope global nexthop via 192.168.1.1 dev eth1 weight 1 nexthop via 192.168.0.1 dev eth2 weight 4