What I'm going to describe is the procedure for viewing linux X applications on the Plan 9 desktop. Other operating systems are supported but I have no use for them and as a result, no experience.
Firstly, you'll want to download the vncserver from http://www.tightvnc.com/download.html and install it in your system I copied the files to /usr/local/bin, you do what's best for your system.
Secondly, on the linux machine you'll want to type (and should see something like):
$ vncserver -geometry 1024x768 New 'X' desktop is linux:1 Starting applications specified in /home/sah/.vnc/xstartup Log file is /home/sah/.vnc/linux:1.log
There are a multitude of settings for the vncserver, but just the above seems to work fine. The first time you start up the vncserver you'll be asked to specify a password to access the desktop.
Log out of the linux box above and in the same terminal window, type:
term% vncv linux:1
provided linux is a system defined in your /lib/ndb/local. Otherwise, just use the ip address of the machine.
The really nice thing about vnc is that updates are client-triggered so the server never goes down for lack of input. If you disconnect from it for days on end and then resume the connection with:
term% vncv linux:1
(staying with the above example), you get your exported desktop just as it was when you left it.
Problems can happen on X11 systems, when you want to use the clipboard between e.g. Firefox and Plan 9, where Firefox uses a different clipboard buffer than the VNC server. The manual solution for this is to use xcutsel(1) on the non-Plan 9 system. You can find an automatic solution at http://www.nongnu.org/autocutsel/, that gets the two clipboards into sync, on change.
If you want your connection secured by TLS, you can use tlsclienttunnel (described in the tlssrv(8) man page) to encrypt and authenticate your connection. You need a tls tunnel application on the unix machine, e.g. stunnel ( http://www.stunnel.org ). Add a section to stunnel's config file like this:
[vnc] accept = 7777 connect = 5901
Change the accept port to your preferences. Create a thumb file for your vnc server's fingerprint. We will fill it later. Now establish the connection with
tlsclienttunnel tcp!yourhost!7777 tcp!localhost!5901 vnc.thumb
You will get a response like this:
/bin/tlsclienttunnel: server certificate sha1hash not recognized
Snarf and paste the sha1hash to your thumb file:
echo 'x509 sha1=sha1hash' > vnc.thumb
Now reestablish the tunnel with the tlsclient command above and connect to it securely with