On Wed, May 20, 2026 at 3:49 PM Devine, Harry (FAA) <[email protected]> wrote:
> More details: I read that the password is stored in what appears to be > an encrypted state. At no point do I get prompted for the user password, > however, in the Guac connection settings, the username and password are > configured. So I’m not sure why it’s not passing that along. I’m assuming > that it is. > > > > So I tried a test on the VNC server I have and removed the passwd file > that had the encrypted password in it, and simply echoed the desired > password into passwd as plain text. Now I get the following in the VNC > server log: > > > > Wed May 20 15:34:50 2026 > > XserverDesktop: New client, sock 24 > > Connections: Accepted: 172.26.170.237::36046 > > SConnection: Reading protocol version > > SConnection: Client needs protocol version 3.8 > > SConnection: Processing security type message > > SConnection: Processing security type message > > SConnection: Client requests security type VncAuth(2) > > SConnection: Processing security message > > SConnection: Processing security message > > SVncAuth: Reading password file > > XserverDesktop: Client gone, sock 24 > > *VNCSConnST: Closing 172.26.170.237::36046: No password configured* > > EncodeManager: Framebuffer updates: 0 > > EncodeManager: Total: 0 rects, 0 pixels > > EncodeManager: 0 B (1:-nan ratio) > > Connections: Closed: 172.26.170.237::36046 > > ComparingUpdateTracker: 0 pixels in / 0 pixels out > > ComparingUpdateTracker: (1:-nan ratio) > > > > So what it looks like to me is that both Guacamole and TigerVNC Viewer can > access the password file, but Guacamole doesn’t seem to know how to decrypt > the value in it. Whereas, the TigerVNC Viewer DOES know how to decrypt > it. And the Viewer also prompts for the password. > > > > Does this make sense? How can I actually prove this theory? I have no > way of knowing what Guacamole is actually sending so it’s very hard to > troubleshoot. > > > Well, the thing that puzzles me about this, is that I don't know how Guacamole would know how or where to read a VNC passwd file in order to authenticate to the VNC server. Unless you've modified the guacamole-server (guacd) code, guacd only ever authenticates with the information that is provided in the connection parameters, which is what you see in the Guacamole UI when you manage the connection. And if you've cleared out the username and password in the connection parameters, and you're connecting to the VNC server that requires a username and/or password, you should be getting a prompt for one or both of those (I think VncAuth is password-only, no username). -Nick
