Reliability of Windows XP SP2 WindowsTime service as SNTP Server

[Guest]

I am using my Windows XP SP2 workstation as an SNTP server. I am usinf the
fact that the WindowsTime service uses SNTP as a client to syncronize the
computer time, but it also respondes as a server to SNTP requests.
Intermitantly it starts acting strangly. What happens is that its time
accuracy goes haywire. When checking with a network sniffer (Ethereal), I can
see that the SNTP request and answers arrives at exact 30 seconds interval
(as my test was configured to do), but the NTP packets timestamps data report
values deviating increasingly from the packets arrival time.
Sometimes, disabling and enabling SP2 firewall, or even re-installing the
network adapter, can "fix" the behaviour, but there were times it did not.
Why the network sniffer report the arrival on "exact" 30 seconds
intervals, but NTP time-stamp deviate in up to 1 second in 7 minutes,
increasingly?

 

[Guest]

Apparantly the PC was configured by the DHCP server to have 2 DNS entries,
the 1st was of the secondary domain controller (which had the active DHCP
server) and the 2nd of the primary domain controller.
Moving the DHCP server to the primary domain controller, and configuring
it to set only 1 DNS address - of the primary controller, seemed to have made
the client Windows XP PC work as a better SNTP server.