Our Guacamole server (v1.4.0) died so we recovered what files we could and setup a new server:
Ubuntu 22.04
Guacamole 1.5.0
Tomcat 9.0.73
Proxied via Nginx
openjdk 11.0.18 2023-01-17
We're using LDAP and TOTP authentication.
After getting new server setup our users can login and connect as before however we're seeing websocket errors every minute where user is given red banner with message:
The remote desktop server encountered an error and has closed the connection. Please try again or contact your system administrator.
Checking Tomcat logs I see in catalina.out the following each time:
Exception in thread "Thread-4" java.lang.IllegalStateException: Message will not be sent because the WebSocket session has been closed
at org.apache.tomcat.websocket.WsRemoteEndpointImplBase.writeMessagePart(WsRemoteEndpointImplBase.java:442)
at org.apache.tomcat.websocket.WsRemoteEndpointImplBase.sendMessageBlock(WsRemoteEndpointImplBase.java:314)
at org.apache.tomcat.websocket.WsRemoteEndpointImplBase.sendMessageBlock(WsRemoteEndpointImplBase.java:254)
at org.apache.tomcat.websocket.WsRemoteEndpointImplBase.sendString(WsRemoteEndpointImplBase.java:195)
at org.apache.tomcat.websocket.WsRemoteEndpointBasic.sendText(WsRemoteEndpointBasic.java:37)
at org.apache.guacamole.websocket.GuacamoleWebSocketTunnelEndpoint.sendInstruction(GuacamoleWebSocketTunnelEndpoint.java:152)
at org.apache.guacamole.websocket.GuacamoleWebSocketTunnelEndpoint.access$200(GuacamoleWebSocketTunnelEndpoint.java:53)
at org.apache.guacamole.websocket.GuacamoleWebSocketTunnelEndpoint$2.run(GuacamoleWebSocketTunnelEndpoint.java:253)
We've not made any changes to our RDP or VNC servers or network firewalls so I suspect is some issue with configuration on new Guacamole install. I've ensured the server built with all modules required (including libwebsockets) and have tried a few different Tomcat server versions to see if some bug there.
At this point I'm out of ideas and not seeing much else to try from search engines and would much appreciate any guidance on what else to check.
Edit: Since posting I've also tried:
Error persists
Issue ended up being firewall related
Simply allowing Guacamole to pass through firewall was not maintaining the websocket connection however using NAT to translate the packet did work