Configuring Network Time Protocol (NTP) service

How NTP works

Guidelines for implementing NTP

Primary and secondary time server information

The NTP configuration file

NTP association modes

Configuring NTP

Authenticating NTP peers
    Authenticating NTP runtime reconfiguration

The NTP driftfile

Restricting access to NTP

Using NTP without access to the Internet

Using ntpdate to set the time

A simple NTP configuration scenario

A complex NTP configuration scenario

Testing and tuning NTP

NTP query commands
    Examples of using ntpq and xntpdc

Troubleshooting NTP

Running mixed synchronization subnets

NTP glossary

For more about NTP