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Friday, January 8, 2010

VNC - Failed to Connect to Server
1. vnc running as service on 5900
2. accept connections is ticked
3. password is set
4. display number and/or port set to auto
5. router port forward to correct internal ip which is static
6. zone alarm has been shut down
7. windows firewall disabled
Lookup server address ... Failed to get server address

If windows firewall enabled on XP SP2:
LAN and dynamic ip or static ip address same story
vnc viewer (vncviewer.exe) can't reach vnc server by hostname
remote desktop connection (mstsc.exe) can't reach remote desktop by hostname
netbios name filtered, hostname blocked by windows firewall XP SP2

workaround over LAN
try to reach ip address instead of the hostname address
disable windows firewall if you have already an NAT/firewall on your router

UltraVNC or any VNC or Remote Desktop is UNUSABLE over ADSL
Since a few weeks (months? ) it looks like that some internet providers LIMIT the bandwidth over ports above 1024... at least in France
(maybe an attempt to counter Peer to Peer ?).
Consequently all the softwares that use TCP or UDP ports > 1024 have become simply unusable over ADSL/Cable connections, even worse than over RTC modems.
When Web browsing still flies...
The solution is to configure your UltraVNC server (or other software) to use ports below 1024 (between 800 and 1024 for instance).
Here is how to configure UltraVNC for port 80 (http port, which will never be limited as it is used for web browsing Wink ). If you already have a web server listening on this port, use a port like 8xy or 9xy.
1. In WinVNC properties page: Ports: Main: 80 (or 8xy)
2. In your router ADSL Modem configuration: you must route port TCP 80 (or 8xy). Restart your modem/router
3. From the outside: run vncviewer with Server = YourServerIP::80 (or YourServerIP::8xy)
-> UltraVNC is flying again Crazy
This trick also works with any software that usually use high ports (like RDP and so on...)

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