VNC: Failed to connect to server

uvnc.com/onlinehelp

Solution 1:

Symtom:
If windows firewall enabled on XP SP2
vncviewer ...Lookup server address ... Failed to get server address !
vncviewer can't reach vnc server by hostname address
remote desktop connection (mstsc.exe) can't reach remote desktop by hostname
Reason:
netbios name filtered, hostname blocked by windows firewall XP SP2
Workaround:
use ip address instead of the hostname address
or
disable windows firewall on XP SP2 if you have already an NAT/firewall on your broadband router,
so you can reach again yours vnc servers by hostname on your local area network (LAN)
manually add DNS IP address to your broadband router
or/and
exclude the vnc server/vnc viewer computer outside of DHCP range or reserve MAC address/hostname to DHCP range

Solution 2:

How to Debug "Failed to Connect to Server" 
How to Debug "Failed to Connect to Server" Version 2 (Updated 2007-4-6)
http://www.bevingtontechnologies.com/www/VNC/docs/debug_faile_to_connect_to_server_using_portqry.doc

http://www.bevingtontechnologies.com/www/VNC/docs/debug_faile_to_connect_to_server_using_portqry.pdf
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How Do I Install UVNC As A Service
WinVNC must be installed and run as a service to be able to do this operation.
You can use the corresponding UltraVNC Server menu shortcut to install this service (from the Start Menu).
You can also do this using Command prompt:
C:\program Files\UltraVNC\WinVNC.exe -install
then :
- reboot the computer
or
- Execute: net start winvnc, in the command prompt.
  WinVNC is installed and run as a service

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To access your computer remotely via VNC, it is necessary to open ports on your firewall :

• 5800
• 5801
• 5900
• 5901

I right clicked the (winvnc) icon in the system tray and chose (kill all clients)
then I double clicked the (Tightvnc viewer-Listen Mode), entered the IP adress and the password as usual ... and it worked.

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uvnc.com/onlinehelp/10.html

installing remotely via MS remote desktop - set password??
install any VNC flavor by remote desktop Terminal Service
and prevent VNC default password not set  

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UltraVNC as a service via RDP will not prompt to set default password no matter what options are chosen. UltraVNC as a service must be installed locally for it to work properly.

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1. I did a RDP connection to my server (which is HEADLESS)
2. I installed ultravnc. At this point I was having all the problems as everybody else
3. With registry editor, I browsed to HKEY_LOCAL_HACHINE\SOFTWARE and then created some the"ORL\WinVNC3\Default" keys (which are case-sensitive and without quotes):
a) created a key named ORL
b) under ORL I created another key called WinVNC3
c) under WinVNC3 I created on last key called Default
4. I then proceeded to install VNC as a service through the start menu, and nothing else (don't fiddle with any more ultraVNC icons for the moment).
5. Download the vncpwd application which you can find at http://www.sysworksoft.net/products/vncpwd.html and unpack it somewhere you can use (or you might just keep it somewhere like c:\windows\system32
6. run vncpwd from the command prompt as follows:
vncpwd /v:
(where is ther password of your choise
7. Restart the computer. This is very, VERY important. Restarding the service didn't worked for me and I was still getting the "no password" error. Only after I restarted the server that things worked out. 

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DO NOT connect to the local console with RDP/TS! That is, DO NOT use mstsc /CONSOLE /V:server ! VNC is not compatible with servers who "have suffered" RDP/TS connect to local console.
I have no problems installing Ultravnc as service (and mirror driver) from remote desktop/TS - if I first populate HKEY_LOCAL_MACHINE/Software/ORL/WinVNC3 with the Password entry copied from another installation.
I have first installed Ultravnc as service on my local PC and configured default password. Then I export HKEY_LOCAL_MACHINE/Software/ORL/WinVNC3 from regedit to a flat file. This file can be copied to the RDP/TS server and imported with regedit. Once this is done, UltraVNC can be installed normally as service, and it will be ready to connect to with VNCviewer and the same default password as the original local PC. Then you can change password/auth.

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create the registry value AuthRequired under HKEY_LOCAL_MACHINE\Software\ORL\WinVNC3 and set it to 0 (a DWORD value). That enabled "passwordless" VNC access, which isn't that bad in my case since I limited it to loopback only anyway (and I can keep the VNC service stopped when not needed). Also, MSLogon seems to work when I enabled that in the registry as well.

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Immediately log in with VNC and start it as a service.
Now since VNC is hooking video as if we were sitting in front of a console rather than RDP's session stuff, we can attach to the newly started vnc service. Go to start->program files->Ultra VNC->Ultra VNC Server [folder]->Show Default Settings (Assuming everything is in the default places/names at least...)
Now set your password. Do a save and get outta there. Exit VNC client locally, and reconnect - now it prompts for password. Remove the authrequired key.