I have four NW6.5 sp5 servers in my tree, called A, B, C, and D. Two of
them are synchronised, and two are getting further and further apart.

I'm using xntpd for Timesync, and have the following layout:

A gets it's time from the university's Stratum 2 NTP servers and has an
NTP.CONF containig

# Time Provider
# server <IP Address>
server NTP0.OX.AC.UK
server NTP1.OX.AC.UK
server NTP2.OX.AC.UK
server NTP3.OX.AC.UK

broadcast key 0

Servers B C and D are Time Consumers of A, with

# Time Provider
server prefer

(The IP address of Server A) in their NTP.CONF files.

DSREPAIR reports that Servers A and B are time-synchronised, while C is
-21 seconds and D is +9 seconds out. Each has widened their gap over the

All three time consumers have XNTPD reporting the following error:

xntpd is unable to service the time request from
Ensure that you have a valid key for this operation.
receive: untrusted keyid

What's going wrong with servers C and D?

James Dore,
New College IT Officer