Cisco Cisco IOS Software Release 12.2(27)SBC

To track the state of an IP route and to enter tracking configuration mode, use the track ip route 
command in global configuration mode. To remove the tracking, use the no form of this command.

track object-number ip route ip-address/prefix-length {reachability | metric threshold}

no track object-number ip route ip-address/prefix-length {reachability | metric threshold}

The route to the subnet address is not tracked.

Global configuration

A tracked IP-route object is considered up and reachable when a routing-table entry exists for the route 
and the route is not inaccessible.

To provide a common interface to tracking clients, route metric values are normalized to the range of 
0 to 255, where 0 is connected and 255 is inaccessible. The resulting value is compared against threshold 
values to determine the tracking state as follows:

State is up if the scaled metric for that route is less than or equal to the up threshold.

State is down if the scaled metric for that route is greater than or equal to the down threshold.

The tracking process uses a per-protocol configurable resolution value to convert the real metric to the 
scaled metric. The metric value communicated to clients is always such that a lower metric value is better 
than a higher metric value.

Use the threshold metric tracking configuration command to specify a threshold metric other than the 
default threshold metric.

Object number that represents the object to be tracked. The range is from 1 
to 500.

IP subnet address to the route that is being tracked.

/prefix-length

The number of bits that comprise the address prefix. A slash must precede 
the value.

Tracks whether the route is reachable.

Tracks the threshold metric. The default up threshold is 254 and the default 
down threshold is 255.

12.2(15)T

This command was introduced.

12.2(25)S

This command was integrated into Cisco IOS Release 12.2(25)S. 

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.