Interface Tracking to Remove Static Route from Routing Table

In this blog post we'll see how to monitor an interface for its status based on which a static route can be tracked. The static route will be removed from routing table when the interface goes down

Create tracking object

RTR#conf t

RTR(config-track)# track 10 interface loopback 101 line-protocol

RTR(config-track)# delay down 5 up 10

RTR(config-track)# exit

In the above commands, delay indicates that the tracking will wait for 5 seconds after the interface goes down before updating the tracking status as down. And it will wait for 10 seconds after the interface comes up before making the tracking object as up.

Attach tracking object to static route that needs to be removed from routing table upon interface going down

RTR(config)# ip route 10.200.100.0 255.255.255.0 10.10.20.254 track 10

RTR(config)# exit

RTR# show track

Track 10

  Interface Loopback101 line-protocol

  Line protocol is Up

    1 change, last change 00:01:12

  Delay up 10 secs, down 5 secs

  Tracked by:

    Static IP Routing 0

Let's shut down the interface Loopback 101 and verify the tracking status

RTR#show track

Track 10

  Interface Loopback101 line-protocol

  Line protocol is Up, delayed Down (3 sec remaining) ((hw admin-down))

    1 change, last change 00:02:10

  Delay up 10 secs, down 5 secs

  Tracked by:

    Static IP Routing 0

RTR#show track

Track 10

  Interface Loopback101 line-protocol

  Line protocol is Down ((hw admin-down))

    2 changes, last change 00:00:06

  Delay up 10 secs, down 5 secs

  Tracked by:

    Static IP Routing

RTR#show ip route track-table

 ip route 10.200.100.0 255.255.255.0 10.10.20.254 track 10 state is [down]

After shutting down the interface, we can see that tracking object is visible as 'Down' and static route is removed from routing table.