The network time protocol (NTP) is used to synchronize the time on the computers in a network. Accurate time is necessary for the successful operation of time sensitive applications such as Active Directory.
By default, FreeNAS® is pre-configured to use three public NTP servers. If your network is using Active Directory, ensure that the FreeNAS® system and the Active Directory Domain Controller have been configured to use the same NTP servers.
Figure 4.3a shows the default NTP configuration for FreeNAS®.
Figure 4.3a: Default NTP Configuration
If you wish to change a default server to match the settings used by your network's domain controller, click an entry to access its "Edit" button. Alternately, you can delete the default NTP servers and click "Add NTP Server" to create your own. Figure 4.3b shows the "Add NTP Server" screen and Table 4.3a summarizes the options when adding or editing an NTP server. ntp.conf(5) explains these options in more detail.
Figure 4.3b: Add or Edit a NTP Server
Table 4.3a: NTP Server Options
|Address||string||name of NTP server|
|Burst||checkbox||recommended when Max. Poll is greater than 10; only use on your own servers i.e. do not use with a public NTP server|
|IBurst||checkbox||speeds the initial synchronization (seconds instead of minutes)|
|Prefer||checkbox||should only be used for NTP servers that are known to be highly accurate, such as those with time monitoring hardware|
|Min. Poll||integer||power of 2 in seconds; can not be lower than 4 or higher than Max. Poll|
|Max. Poll||integer||power of 2 in seconds; can not be higher than 17 or lower than Min. Poll|
|Force||checkbox||forces the addition of the NTP server, even if it is currently unreachable|