IP SLA with EEM not working.

[techguy]

Hi,

I am successfully using IP SLA and EEM for failover. I mean to say that i am monitoring one live public IP address with primary link. If that link goes down, the backup link must goes up by using Event Manager commands.

But when my primary link goes up again after sometime, EEM becomes unable to bring the primary link in use.

 The reason behind is that default route of primary link is absent.

event manager applet TRACK_IF_DOWN
 event track 1 state down
 action 1.0 cli command "enable"
 action 2.0 cli command "clear ip nat trans *"
 action 3.0 cli command "conf t"
 action 4.0 cli command "no ip nat inside source list INTERNET interface f4 overload"
 action 5.0 cli command "ip nat inside source list INTERNET interface vlan999 overload"
 action 6.0 cli command "no ip route 0.0.0.0 0.0.0.0 1.2.3.4"
 action 7.0 cli command "int tu10"
 action 8.0 cli command "tunnel source vlan999"

event manager applet TRACK_IF_UP     -----> is not working
 event track 1 state up
 action 1.0 cli command "enable"
 action 2.0 cli command "clear ip nat trans *"
 action 3.0 cli command "conf t"
 action 4.0 cli command "no ip nat inside source list INTERNET interface vlan999 overload"
 action 5.0 cli command "ip nat inside source list INTERNET interface f4 overload"
 action 6.0 cli command "ip route 0.0.0.0 0.0.0.0 1.2.3.4"
 action 7.0 cli command "int tu10"
 action 8.0 cli command "tunnel source f4"

[jubair151]

Hi,

you are removing the default route when the track goes down, this means that router does not have a route to reach the public ip once the public ip is reachable too ( if the public is not a next hop).

Add one specific route to your public ip only for the tracking purpose, all other traffic ,let is goes through the default route.

Adding only below route should resolve your problem.

Ip route public ip mask 1.2.3.4

[sathvik k v]

Hi,

Removing the default route is causing the problem. You may have to add a static route and track.

Regards,

Sathvik K V

[tanvsult]

I do not see any backup route that you add after removing the primary route. How is the backup route selected? Are you using a route with higher administrative distance or another routing protocol?

One thing what you can do is.. Instead of removing the route, increase the administrative distance of the primary route when the link goes down. And when the link is up you can decrease it again to the default.

Thanks,