There are several commands that can be used to verify interface configuration. The most useful of these is the show ip interface brief command. The output generated displays all interfaces, their IP address, and their current status. The configured and connected interfaces should display a Status of “up” and Protocol of “up”. Anything else would indicate a problem with either the configuration or the cabling.
You can verify connectivity from the interface using the ping command. Cisco routers send five consecutive pings and measure minimal, average, and maximum round trip times. Exclamation marks verify connectivity.
Figure 1 displays the output of the show ip interface brief command, which reveals that the LAN interfaces and the WAN link are all activate and operational. Notice that the ping command generated five exclamation marks verifying connectivity to R2.
Other interface verification commands include:
- show ip route - Displays the contents of the IPv4 routing table stored in RAM.
- show interfaces - Displays statistics for all interfaces on the device.
- show ip interface - Displays the IPv4 statistics for all interfaces on a router.
Figure 2 displays the output of the show ip route command. Notice the three directly connected network entries and the local link interface entries.
Remember to save the configuration using the copy running-config startup-config command.