[rescue] SSH through firewall

Kurt Mosiejczuk rescue at sunhelp.org
Wed Dec 12 12:16:09 CST 2001


On Wed, 12 Dec 2001, Scott Newell wrote:

> >I'm no expert, but wouldn't that weaken SSH? The host key is God.

> Would it?  Instead of always assuming that host secure.net has key #1,
> you'd still check to be sure that:
> 	host secure.net on port 22 has key #1
> 	host secure.net on port 1022 has key #2
> 	host secure.net on port 2022 has key #3
> 	host secure.net on port 3022 has key #4

> Multiple keys per hosts, but each key is associated with that host _and_
> port number.  Or does these scheme leave a big hole for a man in the middle
> attack?

Wouldn't coupling this weaken the ability of SSH to work out through
NAT (technically NPAT).  The port changes through NAT/Masquerading, and
that might cause other problems.  I appreciate the fact that SSH works
through a firewall, protocols that don't work through NAT can be a real
pain.

Now, granted, I'm not positive that SSH uses the host keys on the client
end that way....

--Kurt



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