[ntp:questions] NTP Server Setup

Martin Burnicki martin.burnicki at meinberg.de
Fri Dec 14 08:45:08 UTC 2007


Maarten Wiltink wrote:
> "Prekop, Joe Jr." <PrekoJo at ci.akron.oh.us> wrote in message
> news:514E167644783F4CBCD14C88D4617CCCBAE562 at EX55VM2...
> 
>> I need to configure a Windows 2003 Server as an NTP server.  All of our
>> internal users, servers and network infrastructure equipment will point
>> to this NTP server for updates.  What is the best way to setup a Windows
>> 2003 server as an NTP server?
> 
> Installing NTP on it would seem indicated. And disabling Windows Time,
> and telling it where to get _its_ time.

I appreciate this advice very much. However, there may be circumstances
where it may be preferable to stay with w32time rather than to install NTP.

If the server is a domain controller and the clients (also running w32time,
which is often sufficient for the clients) shall automatically use it as
their time source then it may be wise to keep w32time on the DC. If you
replace w32time on the DC by NTP then the domain members will not
automatically identify the DC as their preferred time server. 

Of course you could configure the clients manually and tell them which time
server to use, but this may be a lot of work if there are a huge number of
clients. Maybe it's possible to set up a group policy for the clients
telling them which time server to use. However, I haven't tried that.

On the other hand, w32time clients will synchronize to a w32time server only
if that server is synchronized. This is similar to NTP and basically a good
thing. 

However, if the time on the DC is disciplined by some other means, e.g. a
radio clock which comes with it's own driver, then the time server service
has to be configured such that it doesn't try to discipline the system
time, too, but just "knows" it is synchronized and passes the time to the
clients.

This is hard to do with w32time. There are some registry parameters which
seem to have been introduced for this purpose. However, some tests here
have shown that it depends strongly on the w32time version whether this
works correctly or not. We have had a case where this worked for exactly 1
day, and then w32time stopped serving the time to its clients.

Configuring ntpd for this scenario is much easier. Just configure the local
clock with a good stratum as the only reference time source, and it's done. 

It's also preferable to install NTP if 

1.) the server is not a domain controller, i.e. there are no clients which
would try to identify their time server automatically

2.) there are other "real" NTP clients which might not synchronize to
w32time, which is (except for very recent versions) just a SNTP server

If you have a Windows domain and you want to use your own reference time
source without much administrative work then you can either:

1.) install a standalone NTP server and configure the PDC to synchronize to
it

2.) install NTP on a different machine, and let the w32time service on the
DC and all "real" NTP clients synchronize to that machine

Martin
-- 
Martin Burnicki

Meinberg Funkuhren
Bad Pyrmont
Germany




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