From what I glean using w32tm /monitor and net time:
The time on our Windows 2000 domain controller (PDC) is syncing properly and with no appreciable delays with the external time server (time.nist.gov), and my local machine (XP SP-3) is sync'd with the DC via ICMP with no delay.
But it seems our network is a persistent minute behind the rest of the East Coast.
UDP 123 is not blocked.
What can I do?