How to set VNC security settings using SSH? `No security types supported. Server sent security types, but we do not support any of them`

Question

With the latest Dist-upgrade, it appears the VNC security settings have been changed which means I cannot access my Pi through VNC until they are changed back. I have SSH access.

As the Pi is over 100 miles away I would like to find a way of changing the security settings to enable me to connect with VNC again without having to be present. I remotely connect to a PC on the remote network and I have SSH access to the PI through that PC.

The error I get when trying to connect is "Error in TightVNC Viewer. No security types supported. Server sent security types, but we do not support any of them"

To make the answers to the question as useful as possible to anyone with a similar problem in the future I will phrase it as follows.

Using only SSH how can I ensure I have suitable VNC security settings?

Answer 1

To be able to use a non-compatible realvnc client you have to downgrade the security of the realvnc server to use vnc password authentication. To be able to to this without a desktop connection open a SSH session:

1. Edit the config file in /root/.vnc/config.d/vncserver-x11

2. Add the following lines at the end of the file

   Authentication=VncAuth
   Encryption=AlwaysOff
   Password=e0fd0472492935da
   

3. Restart the server

This will set the authentication with the password: foobar. In order to change the password,

vncpasswd -service

Connection tested with TigerVNC 1.7.1

Answer 2

Try using the realvnc viewer. There is some difference in the security settings between the two which produces that message.

Answer 3

The following steps can be executed from an SSH session:

1. Edit the RealVNC server configuration file:

sudo vi /root/.vnc/config.d/vncserver-x11

2. Insert, edit, or replace the following lines:

Authentication=VncAuth

Encryption=AlwaysOff

3. Choose a VNC server authentication password (does not require sudo):

vncpasswd -print

4. Copy the ENTIRE "Password=...encrypted password..." line and PASTE or REPLACE it into the file:

/root/.vnc/config.d/vncserver-x11

5. RESTART the RealVNC server:

sudo systemctl restart vncserver-x11-serviced

You should now be able to establish a VNC session using TightVNC or any other viewer. Use the password chosen in step 3.

I know this solution is 2 years late, but I'm pissed that nobody else figured it out, because it only took me 4 hours.

Answer 4

A solution to enable TightVNC viewer with this issue is to install and open VNC viewer in Chrome. From there you can access the Pi and its VNC server settings. Go to options, set authentication to "VNC password" and Encryption to "Prefer Off". See https://www.raspberrypi.org/forums/viewtopic.php?t=176408

After that I was again able to use TightVNC.

Answer 5

Disable encryption to use TightVNC or other VNC client

• to not fiddle with root (as always recomended)
• and follow the Ux* best-practices
• for RealVNC Server change the /etc/vnc/config.d/common.custom file with the authentication options

Process:

• digest a VNC password for the config file and grab the output

  vncpasswd -print <password>
  

• edit the default VNC daemon common.custom configuration

  sudo nano /etc/vnc/config.d/common.custom
  

• add the options and the digest obtained with vncpasswd -print to common.custom file

  Authentication=VncAuth
  Encryption=AlwaysOff
  Password=... 
  

• save and restart RealVNC server (or reboot, sometimes its better...)

  sudo systemctl restart vncserver-x11-serviced
  

Note:

• as an SysOp/Dev advise...
• if possible use XRDP...
• it's faster and more secure...
• though there are many situations we must use VNC...