Does VNC require X server running at all times?

For most of you my question will probably be pretty basic (if not stupid), but I'm new to managing anything Linux-based and need to make sure.

I've recently set-up a home server with Ubuntu Server. It stays in the basement (so physical access is constricted), most of the time I connect with it using SSH, and it's configured to work only in "console-mode" with a need to explicitly start SLiM to work with GUI. However, from time to time I could use a graphical interface.

I decided to install a VNC server there and learned that it requires X server to be installed - that's fine. I just can't find any description how it actually works. Will it just start the X server on its own and stop it upon disconnection? Or will the X have to work all the time?

OR should I maybe use X forwarding over SSH? Although aside from this server I use only Windows machines and I've heard that this method may be problematic.

Thanks in advance for any advice.

Xvnc has own X-Server Embedded See: https://unix.stackexchange.com/questions/129432/vnc-server-without-x-window-system It starts own X-Server using a script. vncserver is a script that starts the external X-Server if it is not running.