Verifying Routes

Verifying Routes
Verifying routes is actually a simple item to understand. No matter what routing protocol or,
for that matter, routing protocols the router has in use, the process is the same.
You will first log into the router, which will be in user EXEC mode. You will know you’re
in this mode because the router name will be followed with a > symbol:
2501A>
2501A>show ip route
After you enter the command, the routing table will be displayed:
2501A>sh ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B – BGP D -
EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA
external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 -
OSPF external type 2, E – EGP i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2,
* - candidate default U - per-user static route, o - ODR, P - periodic
downloaded static route T - traffic engineered route
Gateway of last resort is not set
30 Chapter 1  Routing Principles
172.16.0.0/24 is subnetted, 1 subnets
C 172.16.50.0 is directly connected, FastEthernet0/0
C 192.168.24.0 is directly connected, FastEthernet0/0
R 175.21.0.0/16 [120/1] via 10.10.10.1, 00:00:18, Serial0
2501A#
You will now be able to verify all connected, statically defined, and dynamically learned routes.
As you can see, it’s easy to verify the routes the router knows. After discovering the routes
on the router, you can start testing the connectivity to a route.
Remember, if you ever want to clear all the routes in your routing table, use the
command clear ip route *. This will cause your router to purge its routing
table and relearn all active routes. As you’ve seen, this is very useful in case
you want to get the most up-to-date routing information.