SSH nat-forwarded

[Niklas Saers Mailinglistaccount]

Hi,
I've got a firewall that forwards ports to SSH-ports on boxes it protects.
This has been good for all 4-STABLE boxes, but I've recently put up a
CURRENT box. I can SSH to the firewall and from the firewall to the
CURRENT box, but I do not get a proper connection when having it forwarded
through the firewall.

Let's say my external box 'ext' is on 193.1.2.3, my firewall 'fw' is on
193.2.2.1 and my internal CURRENT-box on 192.168.5.1

'fw' masquerades using
"/sbin/natd -interface fxp0 -redirect_port 192.168.5.1:22 5051"

and "firewall":
 ipfw add divert 8668 ip from any to any via fxp0
 ipfw add allow ip from any to any

from 'fw' "telnet 192.168.5.1 22" gives the classic "SSH-1.99"-etc
while from 'ext' "telnet 192.2.2.1 5051" gives no greeting at all. It
listens and terminates the connection after a short while.

Any suggestions to why ssh doesn't connect correctly? I've forwarded other
ports to other services on the same box and it works flawlessly. Thus I
suspect that 'sshd' understands I've forwarded this connection and doesn't
like it the least bit. Can I turn of this hypersensitivity?

Cheers

   Nik