Discussion

8.2 Viewing Routes to a Particular Prefix
Problem
You need to check to make sure the local router has a route to another router in the
network.
Solution
Use the following version of the show route command:
aviva@RouterG> show route 10.0.8.1
inet.0: 18 destinations, 18 routes (18 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both
10.0.8.0/24 *[IS-IS/18] 00:11:18, metric 20
> to 10.0.0.2 via fe-1/0/1.0
Discussion
Often you may want to find out whether the local routing table has a route to a particular
destination, such as when you are trying to figure out the path that traffic is
taking toward a destination. If you include the destination’s address in the show
route command, you see only that route. This recipe shows the route to 10.0.8.1,
which was learned from an IS-IS Level 2 internal route, has a metric value of 20, and
goes through the next hop of 10.0.0.2 over the router’s interface fe-1/0/1. The
header lines for the inet.0 routing table are also displayed, so you see that this routing
table has a total of 18 routes to 18 destinations.
For more information about the route, use the detail option:
aviva@RouterG> show route 10.0.8.1 detail
inet.0: 18 destinations, 18 routes (18 active, 0 holddown, 0 hidden)
10.0.8.0/24 (1 entry, 1 announced)
*IS-IS Preference: 18
Level: 2
Next-hop reference count: 4
Next hop: 10.0.0.2 via fe-1/0/1.0, selected
State:
Age: 11:41 Metric: 20
Task: IS-IS
Announcement bits (1): 0-KRT
AS path: I
This output shows a few more fields of interest. The Next hop field shows that this
next hop has been selected for inclusion in the forwarding table. The State field
shows that this route is active and is an interior route. The AS path field also shows
that the route was learned internally.
Viewing Routes to a Particular Prefix | 257
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