Time, Time protocol

Description Glossary RFCs Publications Obsolete RFCs


Protocol suite: TCP/IP.
Protocol type:Application layer time protocol.
Ports:37 (TCP, UDP).
Working groups:

This protocol provides a site-independent, machine readable date and time. The Time service sends back to the originating source the time in seconds since midnight on January first 1900.

A time request is initiated by connecting to the Time service via TCP or by sending an empty UDP datagram to the Time service.

The reply from the Time service consists of a single 32 bit value.

MAC header IP header TCP | UDP header Time message

Time message:

0001020304050607 0809101112131415 1617181920212223 2425262728293031

Time. 32 bits, unsigned.
The number of seconds since 00:00 (midnight) 1 January 1900 GMT, such that the time 1 is 12:00:01 am on 1 January 1900 GMT; this base will serve until the year 2036.



[IEN 142] Time Server.

[RFC 738] Time Server.

[RFC 868] Time Protocol.

[RFC 956] Algorithms for Synchronizing Network Clocks.


Obsolete RFCs:

Description Glossary RFCs Publications Obsolete RFCs