Why can't I connect my old G4 to my new iMac?
Posted 09/14/2007 at 11:15am
| by The Mac|Life Staff
You’ve got two potential hitches in your VNC giddyap.
First, how old is that G4? OS X’s built-in VNC server first appeared in Mac OS 10.3, so upgrading the G4’s OS might do the trick.
Or you might be setting it up incorrectly. OS X’s VNC server is more or less a free cousin to Apple Remote Desktop, so you configure it in the ARD section of System Preferences’ Sharing pane, using ARD’s custom port scheme - ports 3283 and 5900.
To set up the VNC server, open System Preferences’ Sharing pane. Under Services, check the box next to Apple Remote Desktop (which automatically opens the required ports in your firewall) and then click Access Privileges. On the screen that appears, check the box labeled “VNC viewers may control screen with password” and type in your password.

To use VNC via Apple Remote Desktop, you have to use Apple’s designated TCP and UDP ports, 3283 and 5900.