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Little Known Cisco Troubleshooting Command

indi — Sat, 11 Sep 2010 12:34:55 +0000

There are a lot of commands in the Cisco IOS that you can use for troubleshooting. It depends on what the symptoms are and what networking technology you are using (eg ATM, ethernet, frame relay).

The more common of course are your sh ip int brie, sh run, sh ver, sh controllers etc but there is one that encompasses all of the afore mentioned and more. And even better, it will help you if you need to get help from a colleague or the TAC to solve your problem.

From ‘enable’mode, type in ‘show tech‘ and you will see that quite a long output will be provided (hint: you may want to set ‘term length’ to 0 for this so you cont have to hit the spacebar after each screenful of info. Also log your session so you can save the output).

If you have a look at the output, there is a lot of info there that doesnt make any sense to me, but what you will also see are the result of the more common commands that you would normally use (ie sh run, sh ver etc).

As I said, if you need to reder your problem to someone else, this will be a handy output to provide. Often the TAC will ask for it so it will save time by providing this upfront to them.

Type wrong command, disable dns lookup on Cisco router

indi — Sat, 29 Dec 2007 02:37:17 +0000

How many times have you typed in the wrong command on a Cisco router, and then have to wait while the DNS lookup times out because the route is trying to resolve that ‘domain’?

Yeah me too. Easy to fix …

Simply enter global configuration mode and type

router(config)# no ip domain-lookup

And the result is no more waiting for the DNS searches to time out.

Safety tip to configure Cisco router remotely

indi — Sun, 31 Dec 2006 22:43:39 +0000

Routers at a remote location can be safely configured by using a reload command first. Huh? Read on…..

Before any configuration changes are made, issue a reload command to the remote router:

reload in 30 Instructs the router to reboot in 30 minutes.
or
reload at 00:00 to reload at a specific time.

The idea behind this is that if you lock yourself out of the router whilst configuring it (assuming you have NOT saved any changes), the router will reload and you should be able to access the router again.

If your configuration changes are successful, a reload cancel command will stop the pending reload.