Stopping extensive debug output

[Bojan Zivancevic]

I am commonly using "debug nat" to monitor NAT behavior on the cisco routers (Of course, debugging is disabled as soon as I get the information). But sometimes, the output volume on the terminal console is so heavy that I just can't stop it.

Is there a way to stop the output flooding my screen? Temporarily or permanently.

[duongla]

One way is to telnet to your routers and turn off all debug because by default, debug output is not sent to telnet terminal.

[Richard Burts · Accepted solution]

There are a couple of things I can suggest that may help with your issue. One thing is the possibility that you can restrict what NAT reports. In particular if you are interested in what NAT is doing for some particular addresses there is a feature where you can debug NAT and include an access list identifier in the debug command. If you do this the debug will only report on activity that matches addresses permitted in the access list.

Another technique that I sometimes use if I am going to debug something with lots of output:

- access the router via telnet or ssh.

- do not do terminal monitor so the debug messages will not come to your session.

- be sure that logging buffer is enabled (and perhaps verify that the logging buffer is pretty good size).

- run debug (the debug messages are written to the logging buffer and not to your session).

- use show log to see the debug output.

- turn off debug when finished.

HTH

Rick

[b-ulrich]

Hi, I beleive you can run the command 'logging synchronous' on the line console. This way if the console gets flooded, you may have a chance to at least type in 'un all' to stop the debug.

[Bojan Zivancevic]

I tried to figure out what exactly does this command do, but...

Can you explain to me the benefits of this command?

[Bojan Zivancevic]

Thanks for your help. ACL identifier is a good advice, indeed.

I was always using a larger buffer than the default one, but I guess I will have to increase it further from time to time (for the debugging purposes). :)

THX!