Question

Router configuration - Invalid input message configuring EIGRP

Routers, EIGRP, Router configuration, Wildcard mask, IP routing protocols, Enhanced Interior Gateway Routing Protocol

I enter the following command to configure eigrp using a wildcard mask, and I get the output "invalid input detected at" under the first character of the wildcard mask. This same command works on all other routers in the network. The command seems correct? Why this router?

R2(config)#router eigrp 100
R2(config-router)#no auto-summary
R2(config-router)#network 172.12.123.0 0.0.0.255
^
% Invalid input detected at '^' marker.

Any ideas?

It could be that the Cisco IOS version on your router doesn't support Wildcard masks. Run command SHOW VERSION and make sure you have at least the same IOS version as the other router.