Howto create redundant network on server

Solution 1:

In Linux, this is called a bonded ethernet interface.

The steps here are for Red Hat Linux and hopefully will be similar for other Linux distributions:

Step 1. Create bond0 - ethernet card

#vi /etc/sysconfig/network-script/ifcfg-bond0

DEVICE=bond0
USERCTL=no
BOOTPROTO=none
IPADDR=X.X.X.X
NETMASK=255.255.255.0 
GATEWAY=X.X.X.X
TYPE=Ethernet

Step 2. /etc/sysconfig/network-script/ifcfg-eth0

DEVICE=eth0
BOOTPROTO=none
MASTER=bond0
SALAVE=yes
USERCTL=no

Step 3. /etc/sysconfig/network-script/ifcfg-eth1

DEVICE=eth1
BOOTPROTO=none
MASTER=bond0
SALAVE=yes
USERCTL=no

Step 4 /etc/modprobe.conf

alias bond bonding
options bond0  mode=1 miimon=100

mode=1 means active/passive, and miimon=100 millisecond ping or checks for update.

Step 5. Restart the service.

It'd be a lot simpler to just use bonded ethernet on the 2 nics.