IP Track

[SathishkumarSaravanan0348]

Hello Experts,

I have seen the IP reachablity command as below. 

track 5 ip route 0.0.0.0 0.0.0.0 reachability.

I know that we will track GW IP and once it is down it will choose the alternative path. In this they have done it for the default route. what is the use of it and what happen if did not track the default route.

Regards,

Sathish.

[paul driver]

Hello

tracking is used in conjunction with conditional routing 

it can be applied to certain prefixes so that upon a certain condition the track will be initiated  and and action can be taken depending what what that is-i

could be a removal if a default route - shutting down  of an interface - policy route to name a few 

in your case an example of a conditional track route that’s  applied to a static default route would remove that default static route if the track applied to it lost reachability or communication to whatever its tracking however if you didn’t have tracking applied to that static route then if even if reachability was lost to its specified next hop or interface then the default will still be in the route table and thus could black hole your traffic