The DAYTIME server protocol is described in RFC-867.
The time server is listening on TCP/UDP port 13 and sends an ASCII string (one line, no format defined).
This is the time protocol sent by the NIST time servers, like time-b.timefreq.bldrdoc.gov, or the USNO servers, like ntp2.usno.navy.mil.
The NIST format : is JJJJJ YR-MO-DA HH:MM:SS TT L H msADV UTC(NIST) OTM.
Example: 53746 06-01-11 21:28:49 00 0 0 266.1 UTC(NIST) *
JJJJJ - the Julian Date is : 53746
YR-MO-DA - the Date is : 2006-01-11
HH:MM:SS - the Time in UTC is : 21:28:49
TT - Indication whether USA is on Standard Time (ST) or Daylight Saving Time (DST) : 00 (Standard Time)
L - Leap second at the end of the month (0: no, 1: +1, 2: -1) : 0
H - Health of the server (0: healthy, >0: errors) : 0
msADV - time code advanced in milliseconds to compensate network delays : 266.1
UTC(NIST) - the originator of this time code : UTC(NIST)
OTM - on-time marker : *
The USNO servers returns a string in the format : W Mon DY HH:MM:SS YR.
The TIME protocol, RFC-868
The TIME protocol is described in RFC-868.
The time server is listening on TCP/UDP port 37 and sends a 32-bit binary number (seconds since 1900-01-01 00:00.00 UTC).
This base will serve until time stamp 4294967295, which will be on 2036-02-07 06:28.14 UTC.
Example: 3346003716 , which translates to 2006-01-11 21:28:49.
The standardized data format refers to UTC (Coordinated Universal Time), no other time zones. This protocol cannot estimate network delays or report additional information.
Note: Time stamp on 1970-01-01 00:00.00 UTC (begin of the unix epoch) was 2208988800.
How to do time server queries
Open a socket connection to the time server on port 13 (daytime) or 37 (time), send an empty string (newline), read the result and close the connection. Then look at the result and display.
The PHP-code is easy and should be self-explaining.
Code: Select all
<?php # PHP V4
function query_time_server ($timeserver, $socket) {
/* Query a time server
(C) 1999-09-29, Ralf D. Kloth (QRQ.software) <ralf at qrq.de> */
$fp = fsockopen($timeserver,$socket,$err,$errstr,5);
# parameters: server, socket, error code, error text, timeout
if ($fp) {
fputs($fp,"\n");
$timevalue = fread($fp,49);
fclose($fp); # close the connection
}
else {
$timevalue = " ";
}
$ret = array();
$ret[] = $timevalue;
$ret[] = $err; # error code
$ret[] = $errstr; # error text
return($ret);
} # function query_time_server
?>Code: Select all
<?php
/* Query a time server
(C) 1999-09-29, Ralf D. Kloth (QRQ.software) <ralf at qrq.de> */
$timeserver = "time-C.timefreq.bldrdoc.gov";
$timercvd = query_time_server($timeserver,13);
if (!$timercvd[1]) { # if no error from query_time_server
$timevalue = $timercvd[0];
echo "Time check from time server ",$timeserver," : [<font color=\"red\">",$timevalue,"</font>].<br>\n";
} #if (!$timercvd)
else {
echo "Unfortunately, the time server $timeserver could not be reached at this time. ";
echo "$timercvd[1] $timercvd[2].<br>\n";
} # else
?>Query a time server on port 37 (TIME protocol) :
Code: Select all
<?php
/* Query a time server
(C) 1999-09-29, Ralf D. Kloth (QRQ.software) <ralf at qrq.de> */
$timeserver = "ntp1.sf-bay.org";
$timercvd = query_time_server($timeserver,37);
if (!$timercvd[1]) { # if no error from query_time_server
$timevalue = bin2hex ($timercvd[0]);
$timevalue = abs (HexDec('7fffffff') - HexDec($timevalue) - HexDec('7fffffff')) ;
$tmestamp = $timevalue - 2208988800; # convert to UNIX epoch time stamp
$datum = date("Y-m-d (D) H:i:s",$tmestamp - date("Z",$tmestamp)); /* incl time zone offset */
$doy = (date("z",$tmestamp)+1);
echo "Time check from time server ",$timeserver," : [<font color=\"red\">",$timevalue,"</font>]";
echo " (seconds since 1900-01-01 00:00.00).<br>\n";
echo "The current date and universal time is ",$datum," UTC. ";
echo "It is day ",$doy," of this year.<br>\n";
echo "The unix epoch time stamp is $tmestamp.<br>\n";
} #if (!$timercvd)
else {
echo "Unfortunately, the time server $timeserver could not be reached at this time. ";
echo "$timercvd[1] $timercvd[2].<br>\n";
} # else
?>| time.nrc.ca | ports 37, NTP |
| ptbtime1.ptb.de | ports 13 (local time), 37, NTP |
| ptbtime2.ptb.de | ports 13 (local time), 37, NTP |
| ntp0.fau.de | ports 37, NTP |
| ntps1-0.cs.tu-berlin.de | ports 13 (local time), 37, NTP |
| ntps1-1.cs.tu-berlin.de | ports 13 (local time), 37, NTP |
| ntps1-0.uni-erlangen.de | ports 37, NTP |
| ntp-p1.obspm.fr | ports 13, 37, NTP |
| time.ien.it | ports 13 (local time), 37 |
| ntp.iriti.cnr.it | ports 13 (local time), NTP |
| NIST - US National Institute of Standards and Technology - http://www.boulder.nist.gov/ | |
| time-a.timefreq.bldrdoc.gov | ports 13, 37 |
| time-b.timefreq.bldrdoc.gov | ports 13, 37 |
| time-c.timefreq.bldrdoc.gov | ports 13, 37 |
| time-d.timefreq.bldrdoc.gov | ports 13, 37 |
| USNO - U.S. Naval Observatory - http://www.usno.navy.mil/, tycho.usno.navy.mil/ntp.html | |
| tick.usno.navy.mil | ports 13, 37, NTP |
| tock.usno.navy.mil | ports 13, 37, NTP |
| ntp2.usno.navy.mil | ports 13, 37, NTP |
| gnomon.cc.columbia.edu | ports 13, 37, NTP |
| tick.gatech.edu | ports 13, 37, NTP |