If you’ve ever worked on a Cisco IOS device, you’ve probably encountered the joy that is the terminal monitoring of events. IOS will happily dump bits of information onto the screen (very useful) but it’s also horribly disruptive if you’re typing in a command. Everything disappears into this sea of debug output or other info.
In my case, I often do ISDN Q.931 debugs to find out what’s going on on my voice gateways. I’ve gotten used to it now, but typing ‘undebug all’ whilst a ton of information whizzes by is less fun than it sounds.
Today, I found this useful command:
“logging synchronous”
If you enable that on your vtys or con (or aux) ports, it basically causes IOS to dump the debug still, but it’ll do it on all other lines EXCEPT the one you’re typing on, leaving it alone. I imagine it could cause some slowdowns as it has to draw your command in the same place, whilst interleaving other junk, so it could potentially cause problems on a direct console, but if you remotely telnet (I really should enable SSH one day), it’ll be a lot easier to see what’s going on.
Here’s the gist of what you need to do:
Router(config)#line con 0 Router(config-line)#logging synchronous Router(config-line)#line vty 0 4 Router(config-line)#logging synchronous
Then wr mem as usual.
Easy!