The "normal" version:
Yep. All generic VNC software will conflict with ARD. This is a good note for most admins out there.
The "geek" version:
Tell RealVNC to use port 5901. Look at the "Connection Options" section of the documentation for your server-side os/version.
The "too much information?" version:
Actually, VNC servers and ARD do just fine side by side. (Aside from listening and bonjour advertising and that), both servers are actually inactive until they receive a connection request. The clincher is that any services ...from Apache to ARD reports to SMB to VNC... always need to be listening to different sockets on different ports. In the good old days, VNC servers could actually listen on several ports and would serve at different color depths and resolutions based on the port number of an incoming request. In fact even today, because ARD uses a mostly standards-compliant VNC implementation, it has to use a different port for reports and commands and such so it won't conflict with the inbuilt VNC server.
VNC is usually on port 5900 nowadays. ARD uses 5900 for its VNC without asking. ARD also uses (or has used) 3283, 5432, 5433, and 5988 for reports and other non-VNC communication. (See: Apple's [list of common ports|http://support.apple.com/kb/TS1629].) In my experience, ARD's VNC client can very reliably control standards-compliant VNC servers, though your mileage may vary.
-- To control a non-ARD VNC server via ARD, just do whatever you normally would in ARD. When controlling, it may warn you that the VNC server doesn't support keystroke encryption, etc. but should still work fine.
-- To connect ARD to a VNC service running on a different port, choose "Add by Address… ⌥⇧⌘N" and in the address field, type the domain name or IP address as you normally would, but append a full colon ":" and the port number. For example, jsmith.example.com:5901 would connect to the computer named jsmith but would look for the VNC service on port 5901.
-- To control a Mac which is running the OS's ARD-VNC server from a third-party VNC app, you must have 'plain' VNC access turned server-side (that is, on the Mac to be controlled: System Prefs > Sharing > Remote Management > Computer Settings > "VNC viewers…"). As long as you use a decent client, it should work reliably after that.
I routinely run the standard ARD "Remote Management" services on my servers for normal remote interaction, but then have a Vine Server set up on 5901 with vastly different settings to benefit low bandwidth connections from the internet, from my iPod's VNC client, or through bouncy ssh tunnels.
If you have any other experiences or questions, or especially if anyone wants try any of this and encounters problems, by all means post back.
Cheers, Joel
