HP-UX Internet Services Administrator's Guide (February 2007)

• For enterprise networks that contain many file servers and workstations, the local
time servers must obtain service from stratum-1 servers.
• While defining a relationship between a higher-numbered stratum server and
lower-numbered stratum server, configure the relationship in the higher-numbered
stratum server. For example, if a stratum-3 server is a client of a stratum-2 server,
configure the relationship in the stratum-3 server. This simplifies configuration
maintenance, because configuration of the higher-numbered stratum server changes
often.
Configuring NTP using the Configuration File
This section describes the statements that you can define in the /etc/ntp.conf
configuration file. It discusses the following topics:
• “Configuring Relationships with Other Time Servers” (page 62)
• “Configuring an External Clock” (page 64)
• “Configuring a Driftfile” (page 65)
• “Configuring Authentication” (page 66)
Configuring Relationships with Other Time Servers
The role of a time server depends on its relationship with other servers in the
synchronization subnet. In the configuration file, you can define a role using one of
the following statements for peer, server, broadcast and broadcastclient:
• peer host | IP_address specifies that host must provide time to the local host with
which the local host can synchronize its time, and the local host must also provide
time to the host.
• server host | IP_address specifies that host must provide time that the
local host can synchronize to, and the local host does not provide time to which
the host can synchronize to. (The local host is a client for the host.) Additionally,
you can define server statements to configure external clocks (radio clocks or local
system clocks) for stratum-1 servers. See “Configuring an External Clock” (page 64)
for more information.
• broadcast host | broadcast_address specifies that the xntpd daemon
in the local host transmits broadcast NTP messages to the broadcast_address,
usually the broadcast address on the local network (The local host is a broadcaster.)
You can specify one or more of the following options using the peer, server, or
broadcast statements:
• keynumber
This option specifies that the NTP packets sent to the host are encrypted using the
key that is associated with number. You must enable the authentication feature
62 Configuring NTP