[Q] Using port 80 and firewalls
cbeerse "at" HISCOM.NL
Thu Jun 6 08:45:03 2002
> -----Original Message-----
> From: Peter Teeson [mailto:pteeson "at" rogers.com]
> (0) Yes I have read all the FAQ and Documentation
> (1) I have successfully run both the server and various viewers in
> default mode.
> Servers on WinNT 4.0SP5 and 98SE. Viewers on Mac and
> Win, including Java.
> The problem I am attempting to solve:
> I have to deal with an environment where the server machines are behind
> firewalls and I have no way to alter the ports that are open on those
> However I know that port 80 is open for sure and also port 21. Probably
> port 443 is also open.
And are they free or are they in use?
What protocol is open? vnc needs tcp, not udp.
> So I looked into the VNC documentation and found Q52,53,54 on this
> I also found in the WinVNC server docn the registry key
> section dealng with port number changes.
> On my Win98SE machine I regedited things as follows:
> HKEY_LOCAL_MACHINES\Software\ORL\WinVNC3\Default\AutoPortSelect 0
> HKEY_CURENT_USER\Software\ORL\WinVNC3\AutoPortSelect 0
> HKEY_CURENT_USER\Software\ORL\WinVNC3\PortNumber 50 (hex)
> Then I ran the VNC server on the Win98SE box and tried to
> connect to it from the WinNT box.
> In the viewer I entered 192.168.100.127:-5820 as per the
> docn but the Win98SE keeps getting an GPF.
Try (2^16 - 5820) or (2^32 - 5820) for portnumbers.
You have a working, not-firewall connection: try this port change on this
machine to see if your setup works from the vnc site.
> Now I'm a Mac programmer who is even less than a white belt
> on Windows
> so I would really appreciate some help here on how to solve the
> problem - namely connecting to a Win98SE box that is behind a
> firewall with only ports 80, 21, and 443 available to me.
Bad luck message: if those ports are the only open ports, they are most
likely to be in use:
port 21: ftp
port 80: http
port 443: https
From my point of view, you can best use port 21 as it is useless without
port 20 since ftp uses both ports, one for controll (21) and one for data
Debugging a vnc connection from the viewer side: telnet to the machine at
the proper port (in netscape: telnet://machine:port/) should give a "RFB
xxx.xxx" message. Start doing this at the vncserver machine:
telnet://localhost:port/ or telnet://127.0.0.1:21/ then, on the same
machine, use the real IP address.