PuTTY - two problems

[David Carts]

1. I use PuTTY now, where I used to use telnet, to connect to a
console terminal server. This device doesn't have an explicit
logout/quit function. In telnet, I would use the telnet break key
CNTL-] then a CNTL-D to quit the session. This doesn't work in ssh,
obviously. Is there a way to interrupt the PuTTY ssh session to close
the connection (better than just killing the PuTTY window)?

2. I have successfully established ssh-1 connectivity using PuTTY on
my W2K PC to my console terminal server, but would prefer to use
ssh-2. When I try this the session fails in (I believe) the
Diffie-Hellman exchange. The event log looks like this:

2002-09-27 12:28:03 Looking up host "aaaaaaaa.bb.ccc.com"
2002-09-27 12:28:03 Connecting to 123.145.167.189 port 10002
2002-09-27 12:28:06 Server version: SSH-2.0-OpenSSH_2.9p1
2002-09-27 12:28:06 We claim version: SSH-2.0-PuTTY-Release-0.52
2002-09-27 12:28:06 Using SSH protocol version 2
2002-09-27 12:28:06 Doing Diffie-Hellman group exchange

Putty reports "Connection closed by remote host". What do I try next?

Otherwise, I use PuTTY to connect to several other platforms without
problem. Also, I have sent a similar message to the vendor of the
console server.

Thanks,

David

[Simon Tatham]

David Carts <david...@em.doe.gov> wrote:
> 1. I use PuTTY now, where I used to use telnet, to connect to a
> console terminal server. This device doesn't have an explicit
> logout/quit function. In telnet, I would use the telnet break key
> CNTL-] then a CNTL-D to quit the session. This doesn't work in ssh,
> obviously. Is there a way to interrupt the PuTTY ssh session to close
> the connection (better than just killing the PuTTY window)?

No. The Telnet escape you quote is likely to have a very similar
effect on the remote software to closing the PuTTY window (in either
Telnet or SSH mode). If you were happily doing the former, I'd say
you can just as happily do the latter.

> 2002-09-27 12:28:06 Doing Diffie-Hellman group exchange
>
> Putty reports "Connection closed by remote host". What do I try next?

By sheer coincidence, I added a workaround to PuTTY within the last
two days which allows it to avoid Diffie-Hellman group exchange if
you think the server is having trouble with it. Download the latest
snapshot, and use the Bugs control panel to tell PuTTY that the
server can't deal with DH group exchange. See if that solves your
problem.

(I'm not aware of a known bug with DH GEX in OpenSSH 2.9, so it may
be that the problem is specific to your server installation. An
alternative and possibly better approach would be to look in the
server's syslogs and see if any illuminating messages occur there.
You might find that /etc/ssh/moduli is missing or has the wrong
permissions, for example.)
--
Simon Tatham "I'm cross. I'm going to have a tantrum.
<ana...@pobox.com> <pause> How do I start?" - my uncle