UltraVnc FAQ

VNC is a famous, cross-platform and Free (GPL) software allowing to remotely control your computer(s) over any TCP/IP connection as if you were in front of it. It is very useful for network administration, remote troubleshooting, eLearning and so on.

UltraVNC is an enhanced VNC distribution, for Win32 platforms only (for now), that brings tons of functionalities, and features that were missing in others VNC flavors: File Transfer (since early 2002), Video Driver, Speed, Text Chat and enhanced security (MS Logon, DSM Plugins).

Frequently Asked Questions



Is UltraVNC compatible with other VNC distributions?
Yes, UltraVNC is compatible with others major VNC flavors... But the only way to take advantage of some of its special features (File transfer, MS Logon, DSM Plugin, Cache, Single Window, Server Scaling, Chat) is to use both UltraVNC viewer and server.

About Speed, have you some benchmarks available?
No. Sorry. Maybe later. For now, we suggest that you test it over a LAN or Modem connection. You should find it quite fast...

Is it possible to transfer a whole directory in one operation in the File transfer?
Yes

Does UltraVNC provides encryption of the communication?
No. Not directly. Because we don't want to. But UltraVNC features the DSM Plugin System (Data Stream Modification) and some Strong Encryption DSM Plugins are already available (see the links page). DSM Plugins are really easy to configure and use.

I'm using RC11b (or RC11c) version over slow connections and having mouse cursor performance problems. Where is the "second" dot cursor that was there before?
Over slow connections, you should do the following to get optimal performances: 1. Disable the Video Driver in WinVNC properties page. 2. Run the viewer using this option: vncviewer.exe /dotcursor. Please note that these 2 manipulations are no more necessary with version RC12 and superior.

I've modified the WinVNC Server default Port to "wxyz". How do I tell the Viewer to use this port?
In the Viewer Connection Window, in the VNC Server field, enter: YourServerIPAdr::wxyz (please note the double ":")

I am in a cybercafe, for instance. How can I take control of my machine running a UltraVNC Server at home?
For those that can't install a vncviewer on the machine they are using and that can only use a Web Browser, there's still the possibility of using the Java Viewer that is embedded in WinVNC. To use it, simply enter this URL in the Web Browser (we suppose that you know your home machine IP Address): http://YourHomeMachineIP:5800 You should then be prompted for the VNC password of your home VNC server. You can even do some file transfers with the JavaViewer !

What are the advantages of the additional Video Mirror Driver?
On Win2000 and XP, the Video Hook "Mirror" Driver provides both speed and accuracy for server screen changes detection and ensures hundreds of updates per second. Whatever the activity on this screen, the server CPU rarely exceeds 25%. Most of time the WinVNC CPU load is between 0% and 5%... When using a Viewer in Full screen mode connected to an Ultra Server using the driver, you really feel like you are in front of the real server!

Can I use UltraVNC without the Video Drivers under W2000/XP?
Yep. Of course. In this case you get quite good performances but for more CPU.

I'm quite confused with all these "Update Handling" methods in WinVNC properties...
Ok, let's sum up. There are 4 different update handling methods in UltraVNC. Note that they are automatically adjusted in UltraVNC v1.0.0, depending on the context, in order to ignore settings redondancy.

  • Poll Fullscreen - All Win versions. Optimized (since eSVNC), it doesn't take too much CPU and is really fast (several dozens of updates per second) for an average accuracy. This option should be systematically selected as it is ignored when a better method is available/selected. The additional Polling methods should be let as configured by default.
  • HookDll - All Win Versions. Original VNC method, good but not perfect as it doesn't detect all screen modifs. This option should always be checked as it is ignored when a better method is available/selected. Activated when "System HookDll" is checked (WinVNC Properties page). If no driver is used, it is suggested to always use this option along with the Poll Fullscreen option. Ddihook Driver - For Win9x only. A small driver than doesn't need special install and that is much better than hookdll and for less CPU load. Activated when "Video Driver" is checked (WinVNC Properties page) under Win9x servers.
  • Video Hook Driver - for W2000/XP only. Provides maximal speed and accuracy in changes detection for very low CPU activity. When this option is checked, all the others update handling methods are ignored. These high performances are above all interesting over fast connections (LAN). Because of the high mouse cursor updates rate (no Tight Local Cursor here), this driver shouldn't be used over slow/modem connections (automatically switched off in WinVNC). Activated when "Video Driver" is checked under W2000/XP servers and the Video Hook Driver is correctly installed.
  • Low Accuracy (Turbo Speed) - All Win versions. When this option is selected, WinVNC only checks half the pixels in the screen regions it scans for changes. The result is -most time- a big speed boost, better responsiveness and some occasional temporary "ghost pixels" in the viewer. Low Accuracy is not recommended when Video Hook Driver is used: no noticeable speed boost but a lot of temporary "ghosts pixels"...

Sending CTRL-ALT-DEL to the server does not work. Why?
WinVNC must be installed and run as a service to be able to do this operation. Use the corresponding UltraVNC Server menu shortcut to install this service (from the Start Menu).

Why implementing a Text Chat when it's so simple to use Notepad?
I've been practicing the "notepad" trick for years and became tired with it for several reasons:

  • Both users can't write at the same time (the mouse and keyboard are shared between the viewer and the server). You must use a protocole like: my turn, over, your turn, over... Lot of confusion and wasted time. This problem disappears with Ultra Chat.
  • The user that is on the server can't chat with several people (viewers) at the same time, except in "broadcast mode" where all users see all messages in a single notepad window! On Ultra Server, a separate Chat window can be opened for each connected viewer.
  • Over modem connections, notepad windows can be a nightmare because of scrolling: you type a new character then the whole window scrolls sending several KiloBytes of graphical data over the slow connection... Ultra Chat only sends ASCII chars.