Multiple Gateway of last resort for backup internet connection on Cisco router

First remove any existing Gateway of last resort

no ip route 0.0.0.0 0.0.0.0

Add gateway of last resort (Primary)

ip route 0.0.0.0 0.0.0.0 1.1.1.1 1 track 1

Add secondary gateway (backup line)

ip route 0.0.0.0 0.0.0.0 2.2.2.2 2 name DSL_Backup

//Setup unrechability detection for redundancy
//Setup monitoring of Primary line with ping to 8.8.8.8

ip sla 100
icmp-echo 8.8.8.8 source-interface Gix/x
frequency 10

Start monitoring Primary line now

ip sla schedule 100 life forever start-time now

Finally add a track entry for sla to cause the gateway switch if Primary fails

track 1 rtr 100 reachability

Check your configuration by executing below command

show ip sla statistics 100

Check the current Gateway of last resort

show ip route

Disrupt the Primary line and see if your configuration works. Your secondary line will kick in after 10 seconds. Primary gateway will always preempt so when your Primary line comes online, your Gateway also changes to Primary gateway.

Leave a Reply

Your email address will not be published. Required fields are marked *

Scroll to top