– Tested with Raspberry Pi OS (buster) on July 2020 – – Updated for Raspberry Pi OS (>=bullseye) on August 2024 –
When trying to connect from your Linux machine using Remmina to a Raspberry Pi running Raspberry PI OS with RealVNC enabled you get the error
Unknown authentication scheme from VNC server: 13, 5, 6, 130, 192
RealVNC only supports a few security schemes. Authentication=VncAuth seems to be the only scheme that allows direct connections from VNC-compatible Viewer projects from third parties. In order to change to VncAuth scheme in your Raspbian and set a password to accept connections from Remmina VNC plugin, open a SSH session (or a terminal window) on the Raspberry and generate your VNC password.
If you are using a recent version of Rasberry Pi OS, run the command:
sudo vncpasswd -service -legacy
otherwise, just run:
sudo vncpasswd -service
Now, edit the file /root/.vnc/config.d/vncserver-x11
sudo nano /root/.vnc/config.d/vncserver-x11
and add the following line at the end of the file:
Authentication=VncAuth
Now your config file should look more or less like mine:
_AnlLastConnTime=int64:0000000000000000 _LastUpdateCheckSuccessTime=int64:01d65c12272dff1a _LastUpdateCheckTime=int64:01d65c12272dff1a Password=c3abbea3b003a0b231737c0541892d72 Authentication=VncAuth
c3abbea3b003a0b231737c0541892d72 is the encrypted version of raspberry; your line will be different.
If you are using a recent version of Raspberry Pi OS, also add the following line at the end of the file:
Encryption=PreferOn
After these edits (not before!), restart the VNC server service with
sudo systemctl restart vncserver-x11-serviced
and you are ready to connect to you Raspberry Pi using Remmina.