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man pages section 8: System Administration Commands

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Updated: Wednesday, July 27, 2022



in.timed - UDP or TCP time protocol service daemon






The in.timed service provides the server-side of the time protocol. The time server sends to requestors the time in seconds since midnight, January 1, 1900. The time protocol is available on both TCP and UDP transports through port 37.

The in.timed service is an inetd(8) delegated smf(7) service. The in.timed detects which transport is requested by examining the socket it is passed by the inetd daemon.

TCP-based service

Once a connection is established, the in.timed sends the time as a 32-bit binary number and closes the connection. Any received data is ignored.

UDP-based service

The in.timed listens for UDP datagrams. When a datagram is received, the server generates a UDP datagram containing the time as a 32–bit binary number and sends it to the client. Any received data is ignored.


The protocol used by in.timed represents time as an unsigned 32-bit number of seconds ranging from January 1, 1900 to February 7, 2036. Another method of time synchronization must be used for dates past the end of this range.

For most purposes, NTP is strongly recommended over this service. For more information, see the ntpd(8) man pages.


See attributes(7) for descriptions of the following attributes:

Interface Stability

See Also

attributes(7), smf(7), in.daytimed(8), inetadm(8), inetd(8), ntpd(8)

Postel, J. and K. Harrenstien. RFC 868, Time Protocol. Network Working Group. May 1983. https://tools.ietf.org/html/rfc868


The in.timed service is managed by the service management facility, smf(7), under the service identifier:


Administrative actions on this service, such as enabling, disabling, or requesting restart, can be performed using svcadm(8). Responsibility for initiating and restarting this service is delegated to inetd(8). Use inetadm(8) to make configuration changes and to view configuration information for this service. The service's status can be queried using the svcs(1) command.


The in.timed program and the svc:/internet/time:default service were added in the Solaris 10 3/05 release. Prior to that, support for the time service was provided as a builtin part of inetd(8) since the initial release of Solaris.

Support for IPv6 was added in Solaris 8.

The time service was enabled by default in releases up through Solaris 9, but has been disabled by default since the Solaris 10 3/05 release.