We only have our IP4100s on the local network so I can't help with the offsite configuration. As for the NTP server we use a Windows 2003 server machine but if there is a computer on site with Windows XP (not sure about Vista or 7) it can be set up to act as a NTP. Have you been able to use the "function keys" on the phone. I can use them as speed dials for numbers 10 - 13 but I would like to put features like call park or voice mail transfer on them.