Detect Apple Remote Desktop (ARD) client at server? Our company's security policy requires passwords to be 12 characters. Apple Remote Desktop (ARD) clients have a limit of 8 characters (I'm not sure why, but I think its due to historical reasons).

We want to block Apple Remote Desktop clients because they can't comply with the policy. Here, block means drop the network connection before the client attempts to provide credentials.

Is there a way to reliably detect Apple Remote Desktop (ARD) clients?
to block: you could have your switches filter ports.  though, you might also block vnc if you do 5900.

or to detect, i'd say use something like bonjour browser utility to find services, or nmap to find active ports.  

3283    TCP/UDP     Net Assistant   -   net-assistant   Apple Remote Desktop 2.0 or later (Reporting feature)

5900    TCP     Virtual Network Computing (VNC)
(Unregistered Use)  -   vnc-server  Apple Remote Desktop 2.0 or later (Observe/Control feature)
Screen Sharing (Mac OS X 10.5 or later)