HP-UX Internet Services Administrator's Guide (May 2010)

adjustments, it indicates a network congestion problem. To review this problem, do
the following steps:
1. Run ntpq -p
2. Examine the dispersion statistics.
Common Problems
This section covers typical problems with ntp operation.
Problem 1: No suitable server for synchronization found.
Every NTP time hierarchy must have at least one stratum-1 server configured with an
external time source, such as, an attached radio clock (Netclock/2 WWVB Synchronized
Clock) or the local system clock. If a stratum-1 server in the hierarchy does not exist,
association is not formed. To verify whether the local xntpd is able to form an
association, issue the following command:
/usr/sbin/ntpdate server
The server is the name of a trusted server, such as a peer or high-level (lower stratum)
server. If the local xntpd is unable to form any association, this command returns the
message No suitable server for synchronization found. The possible
causes for this error message is discussed in the following sections.
Time Difference Greater than 1000 seconds
While evaluating incoming time updates, clients and peers reject time from servers or
peers if the time difference is greater than 1000 seconds. If xntpd is configured with
the broadcastclient entry in the /etc/ntp.conf file, xntpd dies if it cannot find
a suitable server after six consecutive polls, or five polling cycles (approximately 320
seconds if using the default polling interval). If xntpd is configured with server
entries in the /etc/ntp.conf file, xntpd dies if it cannot find a suitable server after
five consecutive polls, or four polling cycles. The number of polls for the
broadcastclient entry configuration is one count more than the server entry
configuration because the first successful reception of an NTP message for the
broadcastclient entry adds the timeserver to the list of timeservers.
Because of this behavior, you may have to issue the following command to synchronize
the local system time with another NTP server before starting xntpd:
/usr/sbin/ntpdate server
When a server entry is configured in the /etc/ntp.conf file, xntpd knows the
name of the timeserve and need to wait for only five polls to synchronize with the
timeserver.
The disp value in the ntpq -p command starts at approximately 16000 seconds and
is divided by two when a successful NTP message is received from the timeserver. If
a value lower than 1000 seconds is received, the client or peer attempts to synchronize
with the timeserver and an error message is received about the time difference. The
Troubleshooting NTP 73