Installing and Administering Internet Services

214 Chapter 7

Conﬁguring NTP

Conﬁguration

This section covers the following topics:

• Overview of the xntpd conﬁguration ﬁle and the steps needed to

conﬁgure xntpd.

• Guidelines for conﬁguring a synchronization subnet.

• Descriptions of how to conﬁgure various characteristics of xntpd in

the /etc/ntp.conf ﬁle.

Conﬁguration Overview

When xntpd starts, it reads a conﬁguration ﬁle to ﬁnd out its operating

characteristics. The conﬁguration ﬁle is called /etc/ntp.conf. This ﬁle

is owned by root and is writeable only by root (it is readable by anyone).

Modifying the conﬁguration ﬁle is usually the responsibility of the

system administrator.

To conﬁgure xntpd:

1. Edit the xntpd conﬁguration ﬁle /etc/ntp.conf. You can also use

SAM to conﬁgure xntpd.

Determine how you want to conﬁgure xntpd by reading the rest of

this chapter and the xntpd man page. Then add the appropriate

statements in /etc/ntp.conf.

2. Set the environment variable XNTPD to 1 in the ﬁle

/etc/rc.config.d/netdaemons. This causes xntpd to start

automatically whenever the system is booted.

3. Set the appropriate value for your local time zone in the ﬁle

/etc/TIMEZONE.

4. Run the xntpd startup script with the following command:

/sbin/init.d/xntpd start

5. Run the ntpq program with the -p switch to verify that xntpd is

forming the correct relationships with other NTP hosts. (See

“Querying xntpd” on page 228.)