Preventing putty.exe from accessing the system

[Kristopher March]

Is there a way to prevent putty.exe from connecting to our systems?

I have Ssh1AgentCompatibility set to none in my /etc/ssh2/ssh2config file. Then I do a kill -HUP on the ssh process.

That doesn't seem to give me what I what.

[Craig Rants]

To prevent access to your server you need to modify the sshd.config file. The ssh2config only affects ssh attempts leaving your server. And since putty is a windows client...

Anyway there are few ways to do this
add this:
DenyHosts IPOFPUTTYBOX
or add this:
Protocol 2 (this usually is Protocol 2,1)
or comment out this:
# HostKey for protocol version 1
# HostKey /opt/openssh2/etc/ssh_host_key

One of these should work for you.

GL,
C

[Kristopher March]

I forget to mention that I am running F-secure v3.0.1

And I don't know if that makes any difference.
I'm looking for other ssh config files.

[Kristopher March]

...still not able to prevent putty.exe from accessing our system.

I have everything referencing Sshd1 set to no or none.
Restarting sshd after every change and still not getting what I need.

Anyone else have some ideas?

[Thomas D. Harrison]

Is it possible that PuTTY is using SSH2? You can tell by:

ooo click on the name of a Saved Session
ooo and then on
ooo Click on the SSH category on the left.
ooo This screen should tell you if the preferred protocol is SSH1 or SSH2.

I can't really think of any way that the HP box could distinguish between clients if they both use the same protocol.

[Kristopher March]

When testing, I select to connect in with the Ssh1 protocol. It works. I don't know if it just defaults back to protocol 2 if protocol fails fails or not.

[Bill Thorsteinson]

Putty does support SSH2,
which is why I switched to it.

If you want to prevent putty
from connecting to the system
from anywhere shut down SSH.
However, I don't recommend
shutting down SSH.

I have seen some releases of
SSH respond with a password
prompt to SSH1 connections
when SSH1 was disabled. The
correct password did not
provice access.

Check the authorized_keys
files and see if the user
is listed in any of them.

On HPUX 11.x I believe you
can use tcpwrappers to limit
the addresses that can
connect to your server.

You may also be able restict
access on the network router

[Santosh Nair_1]

Another place to check whats going is to righ-click on the menu bar on your putty session and select "Event Log". This will show the negotiations between the client (PuTTy) and the server (sshd). Hope this helps.

-Santosh