[ILUG] sshd problem

[Gavin McCullagh]

On Mon, 19 Apr 2004, Lee Hosty wrote:

> I have a headless Knoppix hd-install upstairs that I access wirelessly. I
> don't use it for much except general playing around. As of yesterday I can
> no longer SSH to it from any of my windows machines. There have been no
> software or hardware changes 

Well, something clearly has changed.

What ssh client is this?  Putty can be a little silent sometimes.
What sshd?  openssh, ssh.com, ...?

Do you get a login prompt and auth fails or do you just get nothing?

Can you telnet to the ssh port on that machine?  You should get soemthing
like this if it can connect to the port.

gavin at mybox gavin> telnet somebox ssh
Trying 192.168.1.10...
Connected to somebox
Escape character is '^]'.
SSH-2.0-OpenSSH_3.4p1 Debian 1:3.4p1-1.woody.3

> on any of these machines in the last week or
> so - it just suddenly stopped working. sshd is running. I can ssh out from
> the machine. All machines can ping each other. I've restarted sshd, and
> rebooted to see if that magically changed anything. iptables has no rules
> currently. I can ssh from my windows machines to the other world. Other
> services (samba, slimserver) are working fine.
> 
> Can anyone tell me what I should be checking?

The issues I've generally come across with sshd are:

1. tcp wrappers?  If it's openssh it likely uses tcp wrappers, ie needs to
be allowed in /etc/hosts.allow, could something have changed here?

2. the server key has changed.  If the server host key changed and the
client has the old key it might refuse to connect depending on the client
setup.

3. Firewall issues.

Gavin

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