Installing and Administering Internet Services

282 Chapter7

Conﬁguring the Network Time Protocol (NTP)

also includes troubleshooting information.

This chapter is divided into two major parts. The ﬁrst part covers basic

concepts and procedures. It is ideal if you have limited experience with

NTP. The sections covered in the ﬁrst part include:

• “Equipment Needed for NTP” on page 283

• “Choosing the Source of Time” on page 284

• “Back-up Time Servers” on page 296

• “Conﬁguring Your Primary NTP Server” on page 296

The second part includes details on more advanced topics. It is ideal for

users with more experience with NTP. The sections covered in the second

part include:

• “Stratum Levels and Time Server Hierarchy” on page 298

• “Conﬁguring NTP using the Conﬁguration File” on page 301

• “Starting and Stopping xntpd” on page 309

• “Using ntpq to Query Systems Running xntpd” on page 310

• “Troubleshooting ntp” on page 313