Still can't change the IP port in WinVNC Matthias.Buecher "at"
Wed, 30 Aug 2000 12:05:03 +0000

Hello Victor,

you were NOT fooled, it is really in the FAQ and docs and you already found
the right registry key in the FAQ: "PortNumber".

This key is NOT generated by default.
Call the VNC settings through the VNC start menu, disable the Auto function
for the Display number and enter any dummy Display number (e.g. 1).
If you check the registry again then "PortNumber" will be there.

On the other hand you can create the setting yourself, "PortNumber" is a
DWORD and contains the real IP Port for the RFB protocol, which is
determined through the stated Display number (5900 + Display = RFB IP Port
and 5800 + Display = HTTP IP Port).

For example if you need the RFB protocol on Port 4000 you need to use
Display number -1900 which is 0xFFFFF894 hex and 4294965396 unsigned
It's a very annoying way to set the ports below 5900/5800 through the VNC
settings, fortunately most VNC viewers understand those negative Display

It's easier to set the wanted RFB Port through the registry, as you can
directly enter the wanted IP Port (e.g. 0x00000FA0 for 4000).
Then you can also get the unsigned decimal Display number through the VNC

- the HTTP Port for the Java Viewer is always 100 Ports lower than the RFB
- VNC operates *ONLY* over the RFB Protocol and Port
- the HTTP Port only uploads the Java Applet which then connects through
the RFB Protocol and Port

Regards and good luck
Matthias "Maddes" Buecher

--- Previous Message ---
Date: Tue, 29 Aug 2000 16:17:13 -0700
From: Victor Reiner <victor "at">
Subject: Still can't change the  IP port in WinVNC

thanks, but the info you supplied didn't help me.  First, the items in the
docs you pointed out refer to Display Port, not IP port.  There are
of ports 5800 and 5900 but not how to change them. Second, there is no
registry entry called PortNumber.  I searched the registries of 3 computers
on which I had installed VNC.  AutoPortNumber exists, but once again refers
to Display Port, not IP.

Has anyone on the list actually changed the IP port in the Windows version
VNC?  I posted a question here  and each person who responded (thanks all)
pointed me to the docs and FAQ (which don't actually contain the needed
info) or had some thoughts but weren't sure.  I chased down the suggestions
from the aforementioned respondents, to no avail.  I'd really appreciate
someone's help who's done it themselves.  Thanks in advance...  -=Victor=-
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