Using Static routes to become backup for IGRP

[mphilpott]

How can I setup a static route to be a backup in case of a failure on an IGRP route. Attempting to add the static route with a higher metric results in nothing being added to the routing table.

[donewald]

IGRP's Administrative Distance is 100 so if you are putting in a static with a higher distance you will not see it in your routing table until your IGRP route goes away for that destination. Make your IGRP route go away for your destination and you should then see your higher cost static in your routing table.

Hope this helps,

Don

[mphilpott]

That help sort of. The problem is I want both the IGRP and the higher value static route to co-exist. If the IGRP route goes down it should then use the static route.

How woulf this me possible

[mphilpott]

AM I not understanding this correctly. The static route is still there but not shown until the IGRP route is down? Is it therefore possible to bring down the IGRP route to test this?

[ttuncaral]

Absolutely. Route entry with higher AD is not shown due to routing policies. If IGRP route is down then static become active and takes control. I recommend you not to check it because I use the same way for backup purposes.

[donewald · Accepted solution]

You could test this with a more specific route if you would like to just test your backup path.

Lets say you have a 192.168.3.0/24 route that IGRP has in it's routing table with a next hop of your primary link. If you make your static for just 1 host "ip route 192.168.3.200 255.255.255.255 105 then traffic for this host would travel across your backup link and you would see this in your routing table. Now you'd need to force this over to your backup for the return path or it would come back over your primary link, assuming that your routing is now symetrical.

Hope this helps,

Don

[ttuncaral · Accepted solution]

adding a static route with higher AD works fine. You could not see it in routing table if major route active. When it fails the backup route will be active and be added to the table automatically.