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NTP (Network Time Protocol) is used to synchronize the system time with other devices over the network, this usually happens in a client-server model.


Install net-misc/ntp:

→ Information about USE flags
USE flag Default Recommended Description
caps No Use Linux capabilities library to control privilege
debug No No Enable extra debug codepaths, like asserts and extra output. If you want to get meaningful backtraces see
ipv6 Yes Adds support for IP version 6
openntpd No Allow ntp to be installed alongside openntpd
parse-clocks No Add support for PARSE clocks
samba No Provide support for Samba's signing daemon (needed for Active Directory domain controllers)
selinux No  !!internal use only!! Security Enhanced Linux support, this must be set by the selinux profile or breakage will occur
snmp No Adds support for the Simple Network Management Protocol if available
ssl Yes Adds support for Secure Socket Layer connections
vim-syntax No Pulls in related vim syntax scripts
zeroconf No Support for DNS Service Discovery (DNS-SD)
root # emerge --ask ntp

Or alternatively, you can use net-misc/openntpd instead.


The only configuration file is /etc/ntp.conf which is well explained with comments. Here are some of the more important settings.


Here you can specify with which servers you want to synchronize your local time.


Time zones and location of the server do not matter, it synchronizes the UTC time.

Per default the gentoo servers are listed and enabled. A list of available servers can be found here: You can also define a home or company server here, given that ntpd is running and the machine is allowed to.


To control who is allowed to synchronize with this machine and change the configuration, you can change these options.

  • access to NTP service allowed only from localhost.

# To deny other machines from changing the
# configuration but allow localhost:
restrict default nomodify nopeer
  • access to NTP service allowed only from the network.

# To allow machines within your network to synchronize
# their clocks with your server, but ensure they are
# not allowed to configure the server or used as peers
# to synchronize against, uncomment this line.
restrict mask nomodify nopeer notrap


Basic tools and common usage



root # rc-service ntp-client start

To monitor status of the client.

root # rc-service ntp-client status

If ntpd is run as a service, the time will automatically synchronize as long as the difference between the local time and the time on the server is less than 1000s (~17min). So it is pretty common to adjust the time initially to whatever the server time is as a trusted source:

root # ntpd -g -c /etc/ntp.conf
If ntpd is already running, it won't start a second time.


This used to be the client, but its functionality is now moved into ntpd itself. It is purely to set the local time when started and then exits (not a service):

root # ntpdate


Ntpd Service

Add ntpd to the default runlevel to have the time synchronized automatically. There is no need to run a client when the service is running. Make sure you are not running ntp-client or ntpdate.

root # rc-service ntpd start
root #
rc-update add ntpd default

To monitor status of the server.

root # rc-service ntpd status

See also

External resources