Cisco IOS Command Tip – Extremely Useful Show Interface Cisco IOS Commands
by abpalancajr on
in Cisco IOS Commands
To become an effective Cisco network engineer, it is extremely important to master Cisco IOS commands. Of these, the various show interface commands are the most commonly executed by any typical Cisco network engineer (at least those who know what they are doing!) If you work in an environment where speed is critical, this is even more important. When a network issue is reported, I’ll most likely use one of the below commands on the directly connected switch or router to do a basic check before looking at anything else.
show interface description
The sh int desc Cisco IOS command is the one i use most often on Cisco IOS whenever I need to do a quick check on router and switch interfaces. This command works on both routers and switches. It shows a summary of all the interfaces, their status (both physical and protocol) as well as the description. If you named the interfaces properly when setting this up, you can quickly identify if this is likely due to a cabling fault or perhaps something else. Below is a sample of the output. Please note that this command is undocumented (will not show up on the IOS contextual help) in many versions of IOS, however it does work on most of the IOS versions released in the past few years.
Router#sh int desc
Interface Status Protocol Description
Fa0/0 admin down down To Provider A
Fa0/1 admin down down To Provider B
Fa1/0 up down
Fa1/1 up down
show interface status
The sh int status command is another very useful Cisco IOS command. This shows the status (connected/notconnect), the VLAN, speed and duplex settings as well as type of switchport. This command only works on switchport interfaces (on Cisco Catalyst switches as well as switchport modules on Cisco routers). Very useful when you need to check if the VLAN has been configured correctly as well as whether there are any speed/duplex mismatch or other issues.
Router#sh int status
Port Name Status Vlan Duplex Speed Type
Fa1/0 notconnect 1 auto auto 10/100BaseTX
Fa1/1 notconnect 1 auto auto 10/100BaseTX
Fa1/2 notconnect 1 auto auto 10/100BaseTX
I hope you found this CCNA tip useful. Please feel free to subscribe to my RSS feed or follow me on twitter (@savvynetcert) for more CCNA tips and tricks and CCNA materials.
Cheers,
Francis (SavvyNetCert.Com)
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