NO authentication mode.

[Malcky]

I want to run ultravnc without authentication. I understand that it's risky but I know what I am doing and I have a specific reason for doing so. What do I have to do in order to have the VNC server work without authentication?

[redge]

registry modification
Local machine-specific settings. Options specified here are not overridable. Location:

HKEY_LOCAL_MACHINE\Software\ORL\WinVNC3\

AuthRequired
DWORD decimal value 0 = disable null password checking
DWORD decimal value 1 = enable null password checking (default)

By default, all WinVNC servers will not accept incoming connections unless the server has had its password field set to a non-null value. This restriction was placed to ensure that misconfigured servers would not open security loopholes without the user realising. If a server is only to be used on a secure LAN, however, it may be desirable to forego such checking and allow machines to have a null password. Setting this registry value to zero will disable null-password checking by WinVNC. Local machine-specific setting.

source:
http://www.realvnc.com/products/free/3.3.7/winvnc.html

[themaster1]

Sorry for reviving this old but interesting thread

I'd like to try what redge has suggested (change the value to 0) but i don't see the folder (WinVNC3) in the registry or any ultravnc folder for that matter

HKEY_LOCAL_MACHINE\Software\ORL\WinVNC3\

[Rudi De Vos]

That's a very old thread, we don't use the registry anymore.
All settings are now in ultravnc.ini ( same folder as server)

[themaster1]

I took a look at the .ini, see below:
passwd=0D756AFFD3BF6F715D
passwd2=0D756AFFD3BF6F715D

I tried to change with a simpler pass like 11111 but it don't work it don't keep it somehow then i'm forced to change it manually via the "admin properties" panel.
How can i fix this ?

[Rudi De Vos]

ultravnc.ini contain the encrypted passwd
0D756AFFD3BF6F715D is NOT the password, vnc is able to extract it from this string.

When it seems like you are able to set the password in memory.
Cause:
A temp or ultravnc.ini is not writable for the current desktop user OR the desktop user is a domain user that can not be impersonated by the local system.

Workaround
1) copy winvnc.exe to a writable folder
2) make sure the service not not running ( cmd net stop uvnc_servic)
3) start winvnc and set the password , this create a new ultravnc.ini in the current folder
4) Copy this ultravnc.ini to the program files...
OR
1) logon as local admin
2) set password
On XP, the runas ask permsion the default [v] is " I don't give permission"
f you click OK with [_] you tell the OS that vnc can not change ultravnc.ini.

[themaster1]

That did it for me (1st method) thanks, i'll bookmark this page in case i forget..