HP-UX Internet Services Administrator's Guide (August 2003)
Configuring NTP
Advanced NTP Topics
Chapter 4 81
Configuring an External Clock
Clocks are normally configured with server statements in the
configuration file. You can configure xntpd to support an external clock.
You can insert the clock address anywhere in the configuration file.
Clocks are referenced by an address of the format 127.127.
t
.
u
, where
t
specifies the clock type and
u
specifies the unit number, which depends
on the clock type for interpretation (this allows multiple instances of the
same clock type on a single host).
xntpd supports the following clocks:
• Netclock/2 WWVB Synchronized Clock.
A stratum-1 server is configured with this type of clock. The address
used to configure the clock is 127.127.4.
u
, where
u
is a value
between 1 and 4. You must also create a device file /dev/wwvb%
u
.
• Local Synchronization Clock (pseudo clock)
A system with this type of clock uses the local system clock as a time
source. The address used to configure this clock is 127.127.1.
u
,
where
u
is a value between 0 and 15 and specifies the stratum level
at which the clock runs. When you synchronize the local host to this
clock, the local host operates at one stratum level higher than the
local clock. You can use this type of clock in an isolated
synchronization subnet, which does not have access to a stratum-1
time server.
For more information on configuring external clocks, type man 1M xntpd
at the HP-UX prompt.