What alternatives to VNC are there for Linux? [closed]

Are there (preferably free) alternatives to VNC on Linux?

Is there different remote desktop technologies for Linux or is it all based around VNC?

EDIT: Thanks symcbean for your comment, good point. I find the network performance of RDP much faster than VNC. I am currently using tightVNC, but I do not want to compromise the quality for speed. Using RDP I find that it is just like being infront of the computer. I'm using VNC over an internet connection to a virtual dedicated server, on a broadband connection (admittedly not the fasted broadband in the world - but fast enough) - so in theory there isn't really any serious bottle necks.

-thanks Alex.

If you have a reasonable fast link, X11 is the native remote technology on Linux and every other Unix-type system, as the X11 system was designed from the ground up to work over the network. These days, it's mostly used with ssh port forwarding (like ssh [email protected] -X), and NX, mentioned in the answer by alvosu, "merely" improves on the compression, making it accessible over slow links with a high latency.

NX technology is a computer program that handles remote X Window System connections, and attempts to greatly improve on the performance of the native X display protocol to the point that it can be usable over a slow link such as a dial-up modem. FreeNX - Free Software (GPL) Implementation of the NX Server.

X2Go is a software that enables you to access graphical desktop of a Linux computer. It performs really well even over low bandwidth connections. You can choose to use an entire desktop, or have only a single application (over X11 with a persistent session). If you are familiar with solutions like GNU Screen or tmux for command line sessions, X2Go is a similar tool for graphical sessions. X2Go uses NX technology under the hood.