1258945Sroberto\input texinfo @c -*-texinfo-*- 2258945Sroberto@c %**start of header 3258945Sroberto@setfilename sntp.info 4258945Sroberto@settitle Sntp User's Manual 5280849Scy@include include/version.texi 6258945Sroberto@paragraphindent 2 7258945Sroberto@c %**end of header 8258945Sroberto 9258945Sroberto@ifinfo 10258945SrobertoThis file documents the use of the NTP Project's SNTP, a program for 11258945Srobertoquerying and setting the time. 12258945Sroberto@end ifinfo 13258945Sroberto 14258945Sroberto@direntry 15258945Sroberto* sntp: (sntp). Simple Network Time Protocol 16258945Sroberto@end direntry 17258945Sroberto 18258945Sroberto@titlepage 19258945Sroberto@title Simple Network Time Protocol User's Manual 20258945Sroberto@subtitle sntp, version @value{VERSION}, @value{UPDATED} 21258945Sroberto@c @author Max @email{foo@ntp.org} 22258945Sroberto@end titlepage 23258945Sroberto 24258945Sroberto@c @page 25258945Sroberto@c @vskip 0pt plus 1filll 26258945Sroberto 27258945Sroberto@node Top, sntp Description, (dir), (dir) 28258945Sroberto@top Simple Network Time Protocol User Manual 29258945Sroberto 30258945SrobertoThis document describes the use of the NTP Project's @code{sntp} program, 31258945Srobertothat can be used to query a Network Time Protocol (NTP) server and 32258945Srobertodisplay the time offset of the system clock relative to the server 33258945Srobertoclock. Run as root, it can correct the system clock to this offset as 34258945Srobertowell. It can be run as an interactive command or from a cron job. 35258945Sroberto 36258945SrobertoThis document applies to version @value{VERSION} of @code{sntp}. 37258945Sroberto 38258945SrobertoThe program implements the SNTP protocol as defined by RFC 5905, the NTPv4 39258945SrobertoIETF specification. 40258945Sroberto 41258945Sroberto@shortcontents 42258945Sroberto 43258945Sroberto@menu 44258945Sroberto* sntp Description:: Description 45258945Sroberto* sntp Invocation:: Invoking sntp 46258945Sroberto* Usage:: Usage 47258945Sroberto@end menu 48258945Sroberto 49258945Sroberto@node sntp Description 50258945Sroberto@comment node-name, next, previous, up 51258945Sroberto@section Description 52258945Sroberto 53258945SrobertoBy default, @code{sntp} writes the local data and time (i.e., not UTC) to the 54258945Srobertostandard output in the format: 55258945Sroberto 56258945Sroberto@example 57280849Scy1996-10-15 20:17:25.123 (+0800) +4.567 +/- 0.089 secs 58258945Sroberto@end example 59258945Sroberto 60280849Scywhere 61280849ScyYYYY-MM-DD HH:MM:SS.SUBSEC is the local date and time, 62280849Scy(+0800) is the local timezone adjustment (so we would add 8 hours and 0 minutes to convert the reported local time to UTC), 63280849Scyand 64280849Scythe +4.567 +/- 0.089 secs indicates the time offset and 65258945Srobertoerror bound of the system clock relative to the server clock. 66258945Sroberto 67280849Scy@include invoke-sntp.texi 68258945Sroberto 69258945Sroberto@node Usage 70258945Sroberto@comment node-name, next, previous, up 71258945Sroberto@section Usage 72258945Sroberto 73258945SrobertoThe simplest use of this program is as an unprivileged command to 74258945Srobertocheck the current time, offset, and error in the local clock. 75258945SrobertoFor example: 76258945Sroberto 77258945Sroberto@example 78258945Srobertosntp ntpserver.somewhere 79258945Sroberto@end example 80258945Sroberto 81258945SrobertoWith suitable privilege, it can be run as a command or in a 82258945Sroberto@code{crom} job to reset the local clock from a reliable server, like 83258945Srobertothe @code{ntpdate} and @code{rdate} commands. 84258945SrobertoFor example: 85258945Sroberto 86258945Sroberto@example 87258945Srobertosntp -a ntpserver.somewhere 88258945Sroberto@end example 89