VNC on different port

[Thomas_Knight at adp.com]

My configuration is as follows:

-------         -----------         -----------------         ------
| VNC | --- --- | FreeBSD | --- --- | Work Firewall | --- --- | ME |
-------         -----------         -----------------         ------

I am trying to redirect ports so I can get out through my works firewall
into my VNC Server. I can get it to work on port 8080 but not on 80 or 20 or
21. My work only allows 20, 21, 22, 80 through the firewall. Please see the
example below. 

This does work:
redirect_port tcp 10.0.3.21:5900 166.70.126.172:8080
This does not work:
redirect_port tcp 10.0.3.21:5900 166.70.126.172:80

Any one have any idea's?

Thanks,

Thomas