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Configuring IP Routing in Our Network

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2501C

Router 2501C is directly connected to networks 172.16.40.0 and 172.16.50.0.
The routing table needs to know about networks 172.16.10.0, 172.16.20.0,
and 172.16.30.0. Here is the configuration:

2501C(config)#ip route 172.16.10.0 255.255.255.0

172.16.40.1

2501C(config)#ip route 172.16.20.0 255.255.255.0

172.16.40.1

2501C(config)#ip route 172.16.30.0 255.255.255.0

172.16.40.1

Below is the output of the show ip route command as run on the 2501C

router.

2501C#sh ip route

[output cut]

172.16.0.0/24 is subnetted, 5 subnets

C 172.16.50.0 is directly connected, Ethernet0

C 172.16.40.0 is directly connected, Serial0

S 172.16.30.0 [1/0] via 172.16.40.1

S 172.16.20.0 [1/0] via 172.16.40.1

S 172.16.10.0 [1/0] via 172.16.40.1

2501C#

Now all the routers have the correct routing table, and all the routers and

hosts should be able to communicate without a problem. However, if you
add even one more network or another router to the internetwork, you will
have to update all routers' routing tables by hand. This is fine for a small
network, but it is too time-consuming a task for a large internetwork.

Verifying Your Configuration

Once all the routers' routing tables are configured, they need to be verified.
The best way to do this is with the Ping program. By pinging from routers
2621A and 2501C, the whole internetwork will be tested end-to-end.

Here is the output of a ping to network 172.16.50.0 from the 2621A

router:

2621A#ping 172.16.50.1

Type escape sequence to abort.

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