Some VNC Hacks

• Patches (1.7K) to allow the X Windows VNC server to have a display-only password. These patches apply to vnc-3.3.3_unixsrc.tgz. Simply gunzip and untar this source archive, go into the vnc_unixsrc directory, and do

  $ patch < dopatches
  

  Then make the server and client from scratch. The new facility in the server is enabled with the command-line option -doauth file. This names a secondary password file for authentication. Clients who authenticate using the password in this file will get display-only access to the server, i.e no mouse, no keyboard activity. This option also enables -alwaysshare and -dontdisconnect.

  Here is an example of how to set up a display-only password and how to run the server to use it:

  $ vncpasswd ~/.vnc/dopasswd
  Password:
  Verify:
  
  $ ls -l ~/.vnc/dopasswd 
  -rw-------  1 wkt  staff  8 Oct 29 12:26 /usr/home/wkt/.vnc/dopasswd
  
  $ vncserver -doauth ~/.vnc/dopasswd
  

• Patches (6.3K) to allow the X Windows VNC server to send Zlib compressed data to the X Windows VNC client. This compresses all the data, not just one particular encoding. These patches apply to vnc-3.3.3_unixsrc.tgz. Simply gunzip and untar this source archive, go into the vnc_unixsrc directory, and do

  $ patch < zpatches
  

  Then make the server and client from scratch. The new facility in the Unix client is enabled with the command-line option -zlib N, where N is an integer from 1 to 9. I generally see a compression of 2 to 3 times when using -zlib 9.
  Here are the unzipped patches (23,752 bytes).

• I have done a port of the Zlib compression over to the Windows 95/98 client. Here is the current version of the source code (730K). Treat this as a beta version of the client. It all seems to work very well, but it's pretty new. I'm using VC++ 5.0 as the compiler, and the code is based on vnc-3.3.3r2_winsrc.zip. You can choose the level of compression in the options menu before you connect.

  And here is the client binary (242K). This is my first VC++ compile, so I'd really love to have someone who uses VC++ look at what I'm doing and fix any problems. Please email Warren if you can help me!

• Tum Nguyen has modified the Windows server to perform Zlib compression.

• Finally, here are some details of the design of the zlib compression scheme I've implemented, with references to the X Windows changes.