Q:

Redundant routing (active/backup) on linux

I'm currently trying to setup a redundant routing on RHEL 5.
The target goal is to have a primary route to a subnet and a backup route to that subnet, to be used only if the gateway of the primary route becomes unreachable.
Any idea how to achieve this? Integration with standard RHEL files is a plus here :)
Thanks in advance,

A:

You can use quagga and OSPF
# yum info quagga
Loaded plugins: changelog, fastestmirror, presto, security, versionlock
Loading mirror speeds from cached hostfile
 * base: ftp.colocall.net
 * epel: ftp.colocall.net
 * extras: ftp.colocall.net
 * ius: ius.cu.be
 * rpmforge: ftp.colocall.net
 * updates: ftp.colocall.net
Available Packages
Name        : quagga
Arch        : x86_64
Version     : 0.99.15
Release     : 7.el6_3.2
Size        : 1.1 M
Repo        : base
Summary     : Routing daemon
URL         : http://www.quagga.net
License     : GPLv2+
Description : Quagga is a free software that manages TCP/IP based routing
            : protocol. It takes multi-server and multi-thread approach to resolve
            : the current complexity of the Internet.
            :
            : Quagga supports BGP4, BGP4+, OSPFv2, OSPFv3, RIPv1, RIPv2, and RIPng.
            :
            : Quagga is intended to be used as a Route Server and a Route Reflector. It is
            : not a toolkit, it provides full routing power under a new architecture.
            : Quagga by design has a process for each protocol.
            :
            : Quagga is a fork of GNU Zebra.

And use different weight (cost) for each gateway
router1.example.net# conf t
router1.example.net(config)# int tun0
router1.example.net(config-if)# ip ospf authentication message-digest
router1.example.net(config-if)# ip ospf message-digest-key 1 md5 SHdJLapbQ1
router1.example.net(config-if)# ip ospf cost 10
router1.example.net(config-if)# write
Configuration saved to /etc/quagga/ospfd.conf

router1.example.net# conf t
router1.example.net(config)# int tun1
router1.example.net(config-if)# ip ospf authentication message-digest
router1.example.net(config-if)# ip ospf message-digest-key 1 md5 SHdJLapbQ1
router1.example.net(config-if)# ip ospf cost 20
router1.example.net(config-if)# write
Configuration saved to /etc/quagga/ospfd.conf

