[2024-feb-29] Sad news: Eric Layton aka Nocturnal Slacker aka vtel57 passed away on Feb 26th, shortly after hospitalization. He was one of our Wiki's most prominent admins. He will be missed.
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howtos:window_managers:vnc [2012/10/22 18:08 (UTC)] – created - quick save, had a T3 just drop arfon | howtos:window_managers:vnc [2023/03/13 18:26 (UTC)] (current) – contribute new section starting Xvnc on-demand metaed | ||
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<!-- Add your text below. We strongly advise to start with a Headline (see button bar above). --> | <!-- Add your text below. We strongly advise to start with a Headline (see button bar above). --> | ||
+ | ====== VNC ====== | ||
+ | |||
+ | **NOTE: for the following examples, 192.168.1.34 will be the REMOTE machine (VNC server).** | ||
+ | |||
+ | |||
====== Setup VNC Server (on Slackware)====== | ====== Setup VNC Server (on Slackware)====== | ||
- | USING TightVNC: | + | USING TigerVNC: |
- | On your remote machine, install | + | On your remote machine, install |
- | | + | |
+ | | ||
Start the VNC server: | Start the VNC server: | ||
Line 10: | Line 16: | ||
You should get a message stating that the VNC server has started on DISPLAY 1. | You should get a message stating that the VNC server has started on DISPLAY 1. | ||
- | NOTE: VNC listens to port 5900 or 5901 by default so make sure you can accept connections from that port. | + | **NOTE:** VNC listens to port 5900 or 5901 by default so make sure you can accept connections from that port. |
+ | |||
+ | **NOTE:** If you are using TigerVNC, the server can also listen on port 5800 for web-browser VNC connections. | ||
====== Setup VNC Viewer (on Slackware)====== | ====== Setup VNC Viewer (on Slackware)====== | ||
- | USING TightVNC: | + | USING TigerVNC: |
- | On your local machine, install | + | On your local machine, install |
- | | + | |
+ | | ||
Start the VNC viewer: | Start the VNC viewer: | ||
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- | ====== Tunnel VNC Through SSH (on Slackware) ====== | + | ====== Tunnel VNC Through SSH (from Slackware) ====== |
Open an SSH connection: | Open an SSH connection: | ||
- | ssh -L 5901:127.0.0.1:5901 -N -f -l bob 192.168.1.34 | + | ssh -L 5901:localhost:5901 -N -f -l bob 192.168.1.34 |
< | < | ||
Line 36: | Line 45: | ||
-N : Just forward ports, do not execute a remote command. | -N : Just forward ports, do not execute a remote command. | ||
-f : Make ssh to go to background before command execution. | -f : Make ssh to go to background before command execution. | ||
- | -l bob : ' | + | -l bob : ' |
+ | 192.168.1.34 : is the remote machine (target VNC Server). | ||
+ | | ||
Connect with VNC: | Connect with VNC: | ||
| | ||
- | Enter "192.168.1.34:1" into the 'VNC server:' | + | Enter "localhost: |
- | ====== Tunnel VNC Through SSH (on Windows) ====== | + | ====== Tunnel VNC Through SSH (from Windows |
- | Install Putty on the LOCAL machine. | + | Install Putty on the LOCAL machine. |
- | Open putty and set the following values | + | Open putty and set the following values: |
- | | + | |
- | | + | |
+ | | ||
| | ||
- | | + | |
+ | Connection > SSH > Tunnels > | ||
| | ||
- | | + | |
- | | + | |
- | Auto: checked | + | |
Start the connection by hitting the OPEN button. | Start the connection by hitting the OPEN button. | ||
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Connect with VNC: | Connect with VNC: | ||
| | ||
- | Enter "VNCSERVER_IP/ | + | Enter "localhost: |
+ | |||
+ | |||
+ | ====== Reverse VNC Connection ====== | ||
+ | (Connecting to a listening VNC viewer (Useful for family IT support)) \\ | ||
+ | |||
+ | Start The VNC Viewer (on Slackware) In Listen Mode- \\ | ||
+ | | ||
+ | |||
+ | | ||
+ | |||
+ | ** IF YOUR INCOMING CONNECTION IS COMING THROUGH A FIREWALL (most home routers)** do not forget to forward the port in the router (5500 is the default port for reverse VNC connections). | ||
+ | |||
+ | |||
+ | Start the VNC SERVER on Windows and attach a listening viewer- \\ | ||
+ | Start the VNC Server | ||
+ | RIGHT CLICK on the VNC server icon in your task bar and select " | ||
+ | Put in the IP address of the viewer machine: 192.168.1.34 | ||
+ | | ||
+ | (through a forwarded port), make sure to connect to the ROUTER' | ||
+ | internet address) and NOT your local address. This can be found by going to a | ||
+ | " | ||
+ | |||
+ | |||
+ | |||
+ | ====== Starting '' | ||
+ | |||
+ | A nice refinement is to configure the remote host to automatically create for each user a permanent virtual terminal. | ||
+ | |||
+ | The virtual terminal gets created when the user first connects. The user can detach from their terminal and reattach from elsewhere, providing true persistent terminal service. The terminal persists until either | ||
+ | |||
+ | (i) the user destroys it by logging out, or | ||
+ | |||
+ | (ii) the system operator destroys it by rebooting. | ||
+ | |||
+ | ===== Remote host listener ===== | ||
+ | |||
+ | The remote host needs an '' | ||
+ | |||
+ | 5901 stream tcp wait arfon / | ||
+ | 5902 stream tcp wait metaed / | ||
+ | 5903 stream tcp wait doe / | ||
+ | 5904 stream tcp wait roe / | ||
+ | |||
+ | This arranges that when a VNC viewer connects to port 5901, an '' | ||
+ | |||
+ | If this is the first time you’ve used '' | ||
+ | |||
+ | # chmod 755 / | ||
+ | # / | ||
+ | # pgrep -l inetd | ||
+ | 27849 inetd | ||
+ | |||
+ | ===== Connection procedure ===== | ||
+ | |||
+ | To use, there is a two step procedure. First, the end user connects using '' | ||
+ | |||
+ | $ ssh -L 5901: | ||
+ | |||
+ | Second, the end user connects using '' | ||
+ | |||
+ | I've seen at least one VNC viewer (bVNC) that has builtin support for '' | ||
+ | |||
+ | ===== Display manager configuration ===== | ||
+ | |||
+ | This depends entirely on which display manager you have available, and is really outside the scope of this how-to. Here is just a simple example. Supposing you want to use bog-standard '' | ||
+ | |||
+ | * Open ''/ | ||
+ | * Edit the line '' | ||
+ | * Disable the line by inserting a '' | ||
+ | * Open ''/ | ||
+ | * Edit the line ''# | ||
+ | * Change the '' | ||
+ | * Enable the line by deleting the ''#'' | ||
+ | |||
+ | You might not want your '' | ||
+ | |||
+ | * Open ''/ | ||
+ | * Edit the line '': | ||
+ | * Disable the line by inserting a ''#'' | ||
+ | |||
+ | You will also need to change the remote host’s default runlevel from '' | ||
+ | |||
+ | * Open ''/ | ||
+ | * Edit the line '' | ||
+ | * Change '' | ||
+ | * To make the change immediately without rebooting, run '' | ||
+ | |||
+ | For extra credit, you can customize '' | ||
+ | |||
+ | After authentication, | ||
+ | |||
+ | xterm & | ||
+ | twm | ||
+ | |||
+ | ===== Security considerations ===== | ||
+ | |||
+ | There are several layers of security available to protect the remote virtual terminals from unauthorized use. | ||
+ | |||
+ | ==== Firewall ==== | ||
+ | |||
+ | The first layer of security is the remote host’s firewall. Firewall configuration is outside the scope of this how-to, but here is a brief outline of what you need. The firewall ought to deny remote connections by default. So if you already block all ports by default, no change is needed. You will NOT be punching holes in your firewall to make this work. Supposing your remote host provides only SSH service, and you use the '' | ||
+ | |||
+ | type filter hook input priority 0; policy drop; | ||
+ | ct state vmap { 0x1 : drop, 0x2 : accept, 0x4 : accept } | ||
+ | iifname " | ||
+ | tcp dport 22 accept | ||
+ | |||
+ | With such a firewall in place, you are properly secured. | ||
+ | |||
+ | ==== Encryption ==== | ||
+ | |||
+ | Configured as recommended above, all VNC traffic between the remote host and the local terminal is encrypted, because it travels on the '' | ||
+ | |||
+ | ==== Authentication ==== | ||
+ | |||
+ | There are several authentication layers available. | ||
+ | |||
+ | - An '' | ||
+ | - The terminal can be secured using '' | ||
+ | - The '' | ||
+ | - The user can '' | ||
+ | |||
+ | ===== References ===== | ||
+ | |||
+ | * '' | ||
+ | * '' | ||
+ | * '' | ||
+ | * '' | ||
+ | * '' | ||
+ | * '' | ||
+ | |||
====== Sources ====== | ====== Sources ====== | ||
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