Question

A network administrator configures the interface fa0/0 on the router R1 with the command ip address 172.16.1.254 255.255.255.0. However, when the administrator issues the command show ip route, the routing table does not show the directly connected network. What is the possible cause of the problem?

Answer 1

The possible cause of the problem is that the interface fa0/0 is not in an 'up/up' state. Check the status of the interface using the command 'show interfaces fa0/0'.

If the interface is not up, it won't be added to the routing table as a directly connected network.

Step-by-step explanation:

When a network administrator configures an interface on a router and the network does not appear in the routing table when issuing the show ip route command, there could be several causes.

A common issue is that the interface is not actually "up and running". This can happen if the interface is administratively down, which can be checked with the show ip interface brief command.

Another possibility is that there is a configuration error such as a wrong IP address or subnet mask, which could prevent the network from being listed in the routing table.

Additionally, ensure that no other configurations, like access control lists, are blocking the network's visibility in the routing table. If the interface is up and the configuration is correct, troubleshooting with more specific commands or looking for errors in logs might be necessary.