# GPS Referenced NTP Server SHM



## aevertett (Jun 26, 2014)

I've created a stratum 1 GPS referenced NTP server using an off-the-shelf GPS timing receiver. The GPS receiver is used to post time stamps to the NTP daemon version 4.2.4 using the shared memory interface (SHM). I have written a simple GPS driver to obtain time and date information from the GPS receiver and post it to NTP using SHM. This has been working great with NTP 4.2.4 - no problems whatsoever, regular time-stamps are posted to NTP, which synchronizes to within a few microseconds over a period of a couple of hours. However I have since updated to a later version of NTP, 4.2.6, and have found that synchronization no longer occurs. It appears the NTP server daemon no longer receives the time stamps. Is the NTP shared memory driver broken in NTP 4.2.6? Has anyone else had a similar issue?
Eve


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