SSH connection thru corporate firewall to home sshd on Port 80

From: Bruce Gilmore (bruce.gilmore@dsionline.com)
Date: 02/15/02 

From: "Bruce Gilmore" <bruce.gilmore@dsionline.com>
Date: Fri, 15 Feb 2002 16:31:12 -0600

Hello all. I'm perplexed by the results of an effort to establish a ssh
session and perhaps someone can explain this to me.

I have a FreeBSD server running sshd listening on port 80 at home.
I can successfully establish a ssh session from a Winnt/putty:80 box the
internet to this SSHD:80 server (no firewall involved).
When I take the same Winnt machine behind a corporate firewall which passes
outgoing port 80 connections, I cannot establish a ssh session to the same
sshd:80 home server.

The firewall is a Checkpoint and I've also tested it against an
IPChains/Linux flavor without success.

While testing behind the Checkpoint, I could successfully port scan the
FreeBSD server on port 80 and get a response using nmapNT.
Additionally, I captured the client traffic of the ssh/putty attempt where I
could see the 3-way handshake (syn, syn/ack, ack) with my home server but
nothing more. What gives?

Is the firewall dropping my packets because they are not legit http packets
(i.e. Layer 7 filtering)?

Any other alternatives out there?

Thanks in advance
Bruce Gilmore

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