Day 8: Network Status Verification

Show commands are important in ICND1 so I'll describe some common commands to verify network status:

• show running-config: displays running configuration form RAM on the router.
• show interfaces: displays information about the router interfaces, including encapsulation, address configuration and whether the interface is up or down. I use this one a lot!
• show arp: displays any address resolution protocol entries learned by the router.
• show ip route: displays routes manually configured or dynamically discovered by the router.
• show users: displays any users connected to the router.
• show version: displays the version of Cisco IOS software running on the router, name of image and amount of RAM.

There are also well-known some utilities to use on hosts like:

• ipconfig (ifconfig on Linux).
• ping to test Layer 3 connectivity and basic DNS functionality.
• tracert (on windows)
• traceroute
• netstat show information about devices communicating with a host, including IP address and TCP port information.
• nslookup

Important reminder:
After all this you can test Layer 7 connectivity by accessing the router through SSH, Telnet and a web browser.

There's also some debugging with the debug commands, for example debug ip rip. Stop debugging with undebug all.