Connecting to a telnet server

Rinkhals · Posted: Fri Mar 20, 2009 9:13 pm Post subject: Connecting to a telnet server

I want to run some tests on a telnet server.

For this I want my Gentoo box to accept a telnet session.

I am fully aware of the dangers of using telnet and am also aware that I'm better off using ssh, but, for the purpose of these tests I just want to run a telnet server.

The problem is that after I connect to the Gentoo box it disconnects after 2 or 3 seconds.

I believe that this is because of PAM.

How can I get my server to run?

Many thanks,

Rinki.
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"I'm a Snake if we Disagree" - Jethro Tull, "Bungle in the Jungle"

tony-curtis · Tux's lil' helper Joined: 20 May 2006 Posts: 111

sounds more like a TCP wrappers issue to me at first blush.

do you have the "tcpd" USE flag set (for whichever telnetd)?

Rinkhals · Posted: Sat Mar 21, 2009 7:05 am Post subject:

Tony,

Thanks for the reply

>do you have the "tcpd" USE flag set (for whichever telnetd)?

No I just ran 'emerge netkit-telnetd' without additional arguments.

However, I have just run

tony-curtis · Tux's lil' helper Joined: 20 May 2006 Posts: 111

telnetd is usually handled by inetd, so what's in /etc/xinetd.d/telnetd ? disable = yes, or no?

and is xinetd (a) emerge'd and (b) running?

you can also ask telnetd to tell you some things about what it's doing, e.g. from the command-line

Rinkhals · Posted: Sat Mar 21, 2009 10:35 pm Post subject:

> telnetd is usually handled by inetd, so what's in /etc/xinetd.d/telnetd ? disable = yes, or no?
It was set on 'no': changed to yes.

> and is xinetd (a) emerge'd and (b) running?
xinetd has been started: /etc/init.d/xinetd restart

> in.telnetd -D report -debug 23
> does a "one shot" telnet daemon. When you telnet to localhost in another window you'll get some info that might help.
Not sure I understand. Returns "telnetd: getpeername: Socket operation on non-socket"

Thanks.
_________________
"I'm a Snake if we Disagree" - Jethro Tull, "Bungle in the Jungle"

tony-curtis · Tux's lil' helper Joined: 20 May 2006 Posts: 111

>> telnetd is usually handled by inetd, so what's in /etc/xinetd.d/telnetd ? disable = yes, or no?
> It was set on 'no': changed to yes.

Ahhh, so telnetd was enabled, but now you've turned it off. Well, no matter for testing in the meanwhile...

[I don't think disable=Bool is a good idea, it's a double-negative and is confusing]

>> and is xinetd (a) emerge'd and (b) running?
> xinetd has been started: /etc/init.d/xinetd restart

OK

>> in.telnetd -D report -debug 23
>> does a "one shot" telnet daemon. When you telnet to localhost in another window you'll get some info that might help.
> Not sure I understand. Returns "telnetd: getpeername: Socket operation on non-socket"

Really? Did you enter the whole command-line? If you run in.telnetd on its own, that's the error message you'll get. "-debug <port>" (as in the man page) does a 1-shot and runs the daemon manually.

Rinkhals · Posted: Sun Mar 22, 2009 7:25 am Post subject:

> Ahhh, so telnetd was enabled, but now you've turned it off. Well, no matter for testing in the meanwhile...
So I change it back to 'no' then? It doesn't appear to make any difference to the behaviour, namely that it disconnects immediately after connecting.
I notice that there is an option in the file which says 'wait = no'. If I change this to 'yes' I get the following message just prior to the disconnection:
Get error [10054]: An existing connection was forcibly closed by the remote host.

> Really? Did you enter the whole command-line? If you run in.telnetd on its own, that's the error message you'll get. "-debug <port>" (as in the man page) does a 1-shot and runs the daemon manually.

Sorry. Typo. (I had omitted the '-' in front of debug). It now returns:
telnetd: bind: Address already in use

OK, so I stop xinetd and then run in.telnetd and it works!