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15 votes
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Getting gpsd address for ntpd

It seems that the loopback ip-address range 127.127.0.0/16 is used by NTPD to represent drivers for specific clocks. The third octet is the number of the specific driver as found on the list of ...
HBruijn's user avatar
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7 votes
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are ntp.org pools and time.windows.com safe from gps 2019 week rollover?

There's been a short discussion of the issue on the NTP Pool operators' forum. They don't seem worried. The expected impact is low. If any servers starts serving the wrong time, they will ...
Michael Hampton's user avatar
5 votes

Getting gpsd address for ntpd

All IPv4 addresses in the 127/8 netblock are reserved for host loopback. However, only 127.0.0.1 is commonly used. RFC 5735, section 3. 127.0.0.0/8 - This block is assigned for use as the Internet ...
user's user avatar
  • 4,435
5 votes

Is PTP really more precise than NTP? If so, why?

Yes, it seems possible in principle that NTP can approach PTP. Although, if the requirement is simply sub-second accuracy, NTP can do that over nearly any network. NTP can be very precise, the ...
John Mahowald's user avatar
3 votes
Accepted

chrony and gpsd: socket or PPS connection

First, pps is NOT available via USB. You need to use a direct connection. USB is polled and thus cannot provide an accurate enough signal. I learned this trying to set up some Windows boxes at work....
robin's user avatar
  • 46
2 votes

Using GPS as only source for NTP daemon

Remove the undisciplined local clock source, it is not useful. Disciplined clock with zero peers but known drift will perform better than forcing it to follow undisciplined clock. Determine if ...
John Mahowald's user avatar
2 votes

Setting ntp time from gpsd

gpsd is running as nobody, and so doesn't have privilege to read /dev/ttyUSB0, which is exactly what it's complaining about. If you add the nobody user to the group uucp, that should fix things, but ...
MadHatter's user avatar
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1 vote
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Do NTP pool servers use gpsd?

You could probably work out which of your current upstreams use gpsd by checking their reference id. I don't run gpsd, but some quick web searches suggest that it will probably show up as PPS or GPS. ...
Paul Gear's user avatar
  • 4,467
1 vote

Setting ntp time from gpsd

Be careful that you must "run gpsd on that linked /dev/gps0 so that the GPSD_JSON line appears as expected". So check whether your GPSD run on /dev/gps0 or not. My GPSD run on /dev/ttyS0 on my server ...
JK Zhang's user avatar
1 vote

configuration to use gps time with no internet connection

I would suggest you add true to the server line, among iburst and prefer. Having true lets the server survive NTP's algorithmic weeding of servers. # NMEA refclock driver directly from serial port ...
user00265's user avatar

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