Lairds Computer Services

Most of the time you will be connected to the router remotely via telnet or ssh.  In IOS terms this is a virtual terminal.

Debugging by default logs to the physical serial terminal of the router, so the first thing that you have to do is enable logging on your virtual terminal by issuing the following command:

terminal monitor

This will allow debugging messages to be shown.  The next thing that you should do is to make sure all debugging is turned off before turning on what you need.  To do this you issue the following command:

undebug all

Now you actually have to enable debugging on the router:

conf t
logging monitor debugging
logging on
exit

Now that debugging is enabled on the router and set to display on your virtual terminal you can actually enable debugging for the various protocols as you need.  The comands for this vary by protocol:

debug ip udp
debug ip tcp trans

Finally when you are done, you can turn it all back off by issuing the following commands:

undebug all
terminal no monitor

and then disable logging to the virtual terminal in the config:

conf t
no logging monitor
exit