Breakout key sequence for Cisco

Posted on 2011-10-10
Last Modified: 2012-05-12
I don't always get the same results when trying to exit a telnet session, a traceroute that is timing out etc.

My understanding is the official way is to: hold down three keys all at once ctrl-shift-6 and then release all keys and hit the x key.

It seems that once will not always exit and I must repeat this several times.

I also remember just holding down ctrl-shift-6 and releasing all keys. Do this several times and the router takes me back to the prompt.

Am I just imagining this?
Question by:Dragon0x40
    LVL 17

    Expert Comment

    Yes, the "need to do it several times" does apply to certain things, e.g. during traceroute/ping. Not too sure what priority the break-sequence recognition has in Cisco IOS, but assume that during certain operations, querying for the sequence is not executed, and the sequence does not seem to be buffered, so you need to repeat ... you can stay on the ctrl-shift, though ... doesn't hurt ...

    Author Comment

    so are you saying hold ctrl-shift and press 6 and then x? then let go of ctrl-shift

    Author Comment

    I got into a conversation with someone and I told them you don't need to press x after ctrl-shift-6?

    The documentation says ctrl-shift-6 x.  I thought that might mean ctrl-shift-6 multiple times. As in x amount of times.
    LVL 17

    Accepted Solution

    The "x" is needed to return from a remote session. The ctrl-shift-6 is the actual escape key, following it with another ctrl-shift-6 is the official "break" sequence.
    In telnet mode, there are some additional keys you can press to send special codes:
      ^^B  sends telnet BREAK
      ^^C  sends telnet IP
      ^^H  sends telnet EC
      ^^O  sends telnet AO
      ^^T  sends telnet AYT
      ^^U  sends telnet EL

    Open in new window


    Author Comment

    I looked them up and I am not sure when I would use any of them.

    In this sample output, the first caret (^) symbol represents the Ctrl key, and the second caret represents Shift-6 on your keyboard:

    Break would be three keys ctrl-shft-6 all at once then let go and then hit B?

    I used ctrl-shft-6 and then x to break out of the telnet session.

    ESCAPE SEQUENCE                 PURPOSE  

    Ctrl-^ b                                    Break
    Ctrl-^ c                                    Interrupt Process (IP)
    Ctrl-^ h                                   Erase Character (EC)
    Ctrl-^ o                                   Abort Output (AO)
    Ctrl-^ t                                    Are You There? (AYT)
    Ctrl-^ u                                   Erase Line (EL)

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