From: David L Stewart (D.Stewart@mail.UTexas.edu)
Date: Mon Feb 17 2003 - 21:31:40 GMT-3
EXEC is short for "executive". This is a controlling process
that is spawned when you press enter on a console port or
connect to a vty with telnet. The exec process is what gives
you the command line interface, CLI. If you put "no exec"
on any line, aux, con, tty or vty, you will not get a prompt.
Since Cisco routers are multiuser machines, every user gets
their own exec process when they connect.
"no exec" is only used when you do not want input to spawn an
exec process. Typically this is when you connect the port to
another console for access via reverse telnet (i.e. telnet into
a router and out a serial async port). If you leave exec on
a port and plug it into another port with exec on, they will
usually start talking to each other. Every carriage return
sent by one port gets a response from the other, which gets
a response, etc., thereby locking up the port. Clearing the
connection may stop it, but usually not.
Dave
-
At 1-0:58 AM 2/17/2003, Casey, Paul (6822) wrote:
>Hello,
>
>Can someone please explain the meaning of the no exec command that can go
>under line con 0
>Do I need to use it, I see it on some routers and not on other, does it make
>a difference, if it is there or not,
>Does it have a useful purpose and if so what is it,
>
>Kind regards
>
>
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