Apple Remote Desktop allows you to graphically administer remote OS X machines, including OS X Server. Apple uses some custom encryption over the top of the standard VNC protocol so if you are connecting from a Linux client using vncviewer you’ll get the following error message:
Server did not offer supported security type
To set the Apple Remote Desktop server to use “legacy” VNC mode (i.e. unencrypted passwords), you can SSH into the server (if it’s remote) and execute the following command:
sudo /System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Resources/kickstart -activate -configure -access -on -restart -agent -privs -all -clientopts -setvnclegacy -vnclegacy -yes -setvncpw -vncpw somesecretpassword
Remember that you’re now using VNC in it’s normal mode where passwords are transmitted across the wire in plaintext so if the network you’re connecting across is untrusted, tunnel the connection using SSH or similar.
Hey – the time on your server seems to be a day or so out.