Re: [SLUG] login is lost

From: Ian C. Blenke (icblenke@nks.net)
Date: Thu Nov 14 2002 - 13:41:14 EST


On Thursday 14 November 2002 11:46, you wrote:
> Ok, pay close attention now this is going to be fun.
>
> I get a login prompt at the console of my RH 7.2 installation. I get no
> login prompt if I connect to the box in any other way( via ssh, putty,
> or http). I can ftp from the box to anywhere else, but I cannot ftp
> into the box. I get connection refused.

If you're getting an ftp connection refused, you're not running an FTP server
in inetd.conf/xinetd.conf or running an FTP daemon standalone.

As for not getting a login prompt, it may be a DNS resolution problem. If you
wait 5 minutes, does a login eventually appear? Can you run "ssh -v" and
paste the connection log here?

> I have modems connected to a digiboard running off the serial port and
> they will get the terminal light on if I do "init q'. that lasts for
> about a minute and an half and then the TR light drops out.

TR is DTR (Data Terminal Ready). It's the RS-232 line that is held by the DTE
(Data Terminal Equipment), your PC, when it wishes to be present. A DCE (Data
Communications Equipment) device asserts DSR (Data Set Ready) when it starts
up in response to tell the PC that it is present. If DTR isn't there, the
modem simply will not talk to the port. The same is true from the PC side to
the modem if DSR is missing. This is at a more basic level than RTS/CTS
hardware flow control. Even 3 wire null modem cables use a loop at both ends
to trick the DCE/DTE device that the other end is ready.

When the TR light drops out, your PC is typically rebooting.

> If I use hyperlink and try to connect via modem while the modem tr light
> is lit, I get connected but with not login prompt,, just a blank
> screen,, and no functionality of course.

You need a getty running on that line.

Have you tried debugging with a minicom session on the server with that port
opened? If you can type on one side and see it on the other (full duplex, no
local echo), then the serial port settings are fine and the modem is
connected properly.

If you know you have a good connection, you need to enable a getty on that
/dev/ttyS0 (or whatever your serial device name is). To do this, you must
edit your /etc/inittab and add a getty for that port.

> Any ideas about what is going on? I have turned off the firewall
> through the setup program and still I am effectively locked out.

Serial is different than network. If you cannot ssh or otherwise connect to
the box, my bet is that DNS is a problem - try waiting for 5 minutes and see
if you don't *eventually* get a login.

> And as an aside, samba connections work just fine. But then they do not
> ask for a login.

Samba connections work, and you can login locally, which suggests that PAM is
probably fine. My bet is DNS and a lack of a getty on the port.

We need a bit more info/troubleshooting to get a good feel for the problem.

-- 
- Ian C. Blenke <icblenke@nks.net> <ian@blenke.com>

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