HP-UX Internet Services Administrator's Guide (August 2003)

Configuring NTP
Troubleshooting NTP
Chapter 4 95
For HP-UX NFS Diskless Clusters, the /sbin/init.d/xntpd script on
the diskless clients executes xntpdate to synchronize time with the
diskless cluster server before starting xntpd.
You can also specify a trusted time server explicitly in the file
/etc/rc.config.d/netdaemons, and /sbin/init.d/xntpd will execute
xntpdate, querying the specified time server.
Startup Delay When xntpd is started, it takes five poll cycles (320
seconds using the default polling interval) to form an association with a
higher-level server or peer. During this time window, xntpd does not
respond to time requests from other NTP systems, because it does not
have a suitable time source. This window exists even though xntpd is
using an external clock, which can be either an attached radio clock
(Netclock/2 WWVB Synchronized Clock) or the local system clock
(server 127.127. n.n ).
For external clocks, xntpd does not form a complete association until it
has sent five successful polls to itself using the local loopback address.
Problem 2: Version 1 and 2 NTP Servers Do Not Respond
NTP version 3 packets are ignored by NTP version 1 and version 2
systems. The solution is to indicate the version 1 and 2 system in the
configuration entry on the version 3 system. This informs the version 3
system to use the older message formats when communicating with
these systems.
The following configuration file entries inform xntpd to use NTP version
2 message formats when communicating with some_ver2.sys and NTP
version 1 when communicating with some_ver1.sys.
server some_ver2.sys version 2
server some_ver1.sys version 1
Reporting Problems
Provide the following information while reporting NTP problems:
• The configuration file /etc/ntp.conf (or an alternate configuration
file)
• The /etc/rc.config.d file
• NTP driftfile (if configured)