Why would a system block forwarded ssh & rsync connections?

[Hal Vaughan <hal@thresholddigital.com>]

In short, what could be the problem on a system that is keeping it from 
accepting ssh and rsync connections that are forwarded through a firewall?

More detail:

I think I've narrowed down WHERE the problem is in trying to forward some 
ports through my inside firewall.  This is the last thing I'm trying to 
solve, so an help is appreciated.  I was supposed to have all these systems 
working at the beginning of the week, so I'm falling behind.

I'm forwarding ports through a firewall to a system behind that firewall.  For 
example, I'm forwarding port 60022 on the outside of the firewall to port 22 
(ssh) for a system on the inside.  I get absolutely no response at all.  I'm 
doing the same with port 60873 (rsync).  At one point I had to shut the box 
down and reboot.  While waiting, I tried:

rsync --port=60873 <sysaddress>::

This should have given me a list of directories available for rsync.  Instead, 
while the system was booting, I got a "no route to host" error.  If I try the 
same command while the machine is up, it times out.

So it comes down to something on the machine I'm trying to reach is blocking 
me (I know I can reach it from another system if it is behind the same 
firewall, so I know it'll work).  I've (for now) edited /etc/hosts.deny so no 
hosts are denied.

What else could be a problem that is keeping this system from accepting 
connections for ssh and rsync that are forwarded through a firewall?

Thanks for any help!

Hal