Mailing List Archive: How to make cisco terminal server serve unconnected consoles gracefully?

Hi,

This is obviously not quite a conserver question, rather a question about
how to effectively use a cisco terminal server as a console server (which
I then use with conserver).

When the device to which a console is connected is powered off, the
cisco allows a single connection and then disconnect, but then leaves
the line "logged in" despite the TCP disconnect and so future connections
are refused.

e.g.

conserver>sh line
Tty Typ Tx/Rx A Modem Roty AccO AccI Uses Noise Overruns Int
...
38 TTY 9600/9600 - - - - - 0 0 0/0 -

fenestro% telnet 135.197.18.3 2038
Trying 135.197.18.3...
Connected to 135.197.18.3.
Escape character is '^]'.

conserver line 38 cubix06-console

telnet> quit
Connection closed.
fenestro% telnet 135.197.18.3 2038
Trying 135.197.18.3...
telnet: connect to address 135.197.18.3: Connection refused
telnet: Unable to connect to remote host

conserver>sh line
Tty Typ Tx/Rx A Modem Roty AccO AccI Uses Noise Overruns Int
...
* 38 TTY 9600/9600 - - - - - 2 0 0/0 -
...
conserver>sh users
Line User Host(s) Idle Location
...
38 tty 38 incoming 00:01:01 fenestro.attlabs.att.com

Line 38 is configured as:

line 38
location cubix06-console
no exec
exec-timeout 0 0
transport input telnet
transport output none
flowcontrol hardware

and the terminal server is running

Cisco Internetwork Operating System Software
IOS (tm) C2600 Software (C2600-I-M), Version 12.0(14), RELEASE SOFTWARE (fc1)

Any suggestions would be appreciated.

(Why is this a problem? When a device gets into this state, conserver
can force the line down and so will miss its bootup messages, which might
be important/relevant.)

Thanks,
Bill

Yep, it's a problem. I don't have any great ideas as to how to avoid it
either. All I have to (potentially) offer is a script that will rsh to the
terminal server and clear the lines for you. It's something an acquaintance of
mine wrote and I believe the logic is that it does a 'console -u', looks for
downed consoles, does a 'clear line <blah>' via rsh and then (maybe) sends a
SIGUSR1 to 're-up' all downed consoles. It's something that could be run
occasionally, I suppose. Or, if I can't get a copy of it, the logic is at
least there for someone to write a quick shell script (I'd love to put it in
the contrib directory in the distribution). So, not much help, but maybe a
work-around. If anyone has good cisco knowledge on how to avoid the issue,
that would be wonderful, but I have faith in my cisco experts and they came up
with the above logic, so I kinda doubt there's much of a choice (unless, of
course, the most recent IOS provides something).

Good luck!

Bryan

Quoting Bill Fenner <fenner@research.att.com>:
> This is obviously not quite a conserver question, rather a question
> about
> how to effectively use a cisco terminal server as a console server
> (which
> I then use with conserver).
>
> When the device to which a console is connected is powered off, the
> cisco allows a single connection and then disconnect, but then leaves
> the line "logged in" despite the TCP disconnect and so future
> connections
> are refused.