I need your help very badly. I have give a solution for the requirement. I'm struggling for 5 days to get one. Requirement is to get a solution for redundant network in Linux systems.

We have different devices, clients and servers in the network. Each one can has two ethernet cards connected in them. I have to find a solution that in the linux system if one ethernet connection fails other should be used, like a ethernet redundant system.

For testing this one, we have made small lab setup. We have 4systems in the lab, where eth0 of every system is connected to Switch-1 and eht1 of every system is connected to switch-2. 4Systems means two servers and two clients.

Think that I started communicating with client1 to server1(I really dont know which interface it is either eth0 and eth1), while communicating if I remove one ethernet cable from the client1 the communication should not fail and it should proceed from eth1 of client to any interface of eth0.

For this stuff I have used bonding, but it can be used only when all the devices are in the same network. Also in bonding both the interfaces will have same ip address, netmask and gateway but in my case each cable can be connected to different networks.

Please help me in getting a solution other than Bonding. I will provide the details if you dont understand. I need this very badly I don't have enough time also. Also Please note that there is no physical or virtual connection between switches. So I couldn't do any routing between them.

2 Answers 2


read up on bonding. for simple failover, mode1 (active-backup) is good enough

EDIT: for multiple network access, you can either simply use multihoming (basically in linux that means giving two NICs two IP/Subnet configs) or go for "multi-ISP" solution: http://lartc.org/howto/lartc.rpdb.multiple-links.html

I am aware this is not a connection ot the internet, but there really is no difference.

  • ... but in his question he mentioned bonding and that it is not sufficient -- each cable should be connected to a different network. Nov 9, 2010 at 12:01
  • Yes, you are right Janne I have to put each NIC on different network. This bothers me a lot in finding the solution. Nov 9, 2010 at 12:14
  • You could write a small script to test the connection, drop the interface if its down, bring the other up and fix the routing ? - Kludge, but it'd work ?
    – Sirex
    Jan 19, 2011 at 9:54

You can use OSPF for this. Quagga is an excellent Linux implementation of OSPF that's especially easy to learn if you're familiar with Cisco IOS. Assign each Linux machine a /32 that you use to reach its services and have it inject a route to that /32, using OSPF, over each physical network it is connected to.

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