Remmina VNC Hangs on Connecting to Headless Mini-PC

Question

I am trying to connect a laptop (as client) to a headless mini-pc (as server) both running Ubuntu 16.04 LTS, 64-bit on a home router. I can SSH perfectly fine in terminal or Remmina (after allowing port 22 with ufw) just unable to remotely connect with VNC in Remmina 1.2.0 as dialog hangs.

• Laptop is connected to wifi with active listening ports:

  $ netstat -ln --inet --inet6
  
  Active Internet connections (only servers)
  Proto Recv-Q Send-Q Local Address           Foreign Address         State      
  tcp        0      0 127.0.0.1:5939          0.0.0.0:*               LISTEN     
  tcp        0      0 127.0.1.1:53            0.0.0.0:*               LISTEN     
  tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN     
  tcp        0      0 127.0.0.1:631           0.0.0.0:*               LISTEN     
  tcp6       0      0 :::22                   :::*                    LISTEN     
  tcp6       0      0 ::1:631                 :::*                    LISTEN 
  

• Mini-PC (Intel Celeron, 4-processor, 64-GB HD, 2GB RAM) is connected via ethernet to same router. It boots up without login directly to the root user (at least seen with a temp monitor).

  I tried auto-connecting mini-PC to wifi (even adjusted the /etc/network/interfaces file but not with static IP (could that be issue?) and with a saved wireless profile available to all users but it never connects wirelessly). Below are active listening ports from ssh:

  $ netstat -ln --inet --inet6
  
  Active Internet connections (only servers)
  Proto Recv-Q Send-Q Local Address           Foreign Address         State      
  tcp        0      0 0.0.0.0:5900            0.0.0.0:*               LISTEN     
  tcp        0      0 127.0.1.1:53            0.0.0.0:*               LISTEN     
  tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN     
  tcp6       0      0 :::5900                 :::*                    LISTEN     
  tcp6       0      0 :::22                   :::*                    LISTEN 
  

Below is my setup file where the server is auto-filled per selection in the [...] browse button. And yes, mini-PC does allow remote desktop sharing, view and control.

Upon connecting, my heart leaps as I am prompted for SSH password via tunnel and then the VNC passcode. However, after that the Connecting... dialog as shown below simply hangs forever. My heart sinks. Absolutely nothing happens! No error message, no additional prompts, nothing. Epic frustration.

I tried the IP address for Server as shown by nmap, different hostnames, different ports as shown with netstat, even changes to Advanced in Remmina. Though the hanging dialog does not appear with these other changes, they error out with failed to bind on local port.

No where I found on askubuntu has anyone had the hanging Remmina dialog. Only on this ubuntuforums post with nearly same networking setup touched on the hanging Connect where at end they discussed ports but sadly our good friend leaves us with no closure.

Please advise on how to troubleshoot and being a new Linux user please provide specific command lines as I do not know much of the lingo. Is it port forwarding of internet provider? Is it device hardware issue? Ethernet not compatible with wireless? Firewalls of some kind?

Answer 1

Eventually, I found my answer: no vncserver was installed on the mini-PC (facepalm) and possibly why the Connecting... dialog simply hung waiting for a VNC session.

Simply I did the following:

1. Installed tightvncserver, created vncserver password, and adjusted the startup file.

   $ sudo apt install xfce4 xfce4-goodies tightvncserver
   
   $ mv ~/.vnc/xstartup ~/.vnc/xstartup.bak
   $ gedit ~/.vnc/xstartup
   $ sudo chmod +x ~/.vnc/xstartup
   

2. Then in ssh, started the vncserver on mini-PC.

   $ vncserver
   

3. Finally, on laptop client, I opened the port.

   $ ssh -L 5901:127.0.0.1:5901 -N -f -l username server_ip_address
   

   And then with Remmina I logged in connecting to localhost:5901 entering the ssh password (for tunnel) and vncserver password created above in step #1.