From fe0f98f6ff117c415bb1a45a5c87cb68812751ca Mon Sep 17 00:00:00 2001 From: "Eric S. Raymond" Date: Sun, 8 May 2016 11:31:49 -0400 Subject: Some repairs. --- www/gpsd-time-service-howto.txt | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) (limited to 'www') diff --git a/www/gpsd-time-service-howto.txt b/www/gpsd-time-service-howto.txt index a27de0d0..d880fe91 100644 --- a/www/gpsd-time-service-howto.txt +++ b/www/gpsd-time-service-howto.txt @@ -293,9 +293,9 @@ A normal gpsd build includes support for interpreting 1PPS pulses that is mostly autoconfiguring and requires no special setup. You can build a version stripped to the mimimum configuration required -for time service. This reduces the size of the binary and may - -like this: +for time service. This reduces the size of the binary and may be +helpful on embedded systems or for SBCs like the Raspberry Pi, Odroid, +or BeagleBone. Do it like this: ----------------------------------------------------------------------------- scons timeservice=yes nmea0183=yes fixed_port_speed=9600 fixed_stop_bits=1 @@ -355,7 +355,7 @@ at references. You will need to have either ntpd or chrony installed. If you are running a Unix variant with a package system, the packages will -probably be named 'ntpd' and either 'chrony' or 'chronyd'. +probably be named 'ntp' (or 'ntpsec') and either 'chrony' or 'chronyd'. Of these two, ntpd is the older and more popular choice - thus, the one with the best-established peer community if you need help in @@ -501,7 +501,8 @@ sources to check: == Running GPSD == If you're going to use gpsd for time service, you must run in -n mode -so the clock will be updated even when no clients are active. +so the clock will be updated even when no clients are active. This +is forced if you built GPSD with timeservice=yes as an option. Note that gpsd assumes that after each fix the GPS receiver will assert 1PPS first and ship sentences reporting time of fix @@ -552,7 +553,9 @@ OS distribution has done "secure" things with the permissions. Most Unix systems get their time service through ntpd, a very old and stable open-source software suite which is the reference -implementation of NTP. The project home page is <>. +implementation of NTP. The project home page is <>. We +recommend using NTPsec, a recent fork that is improved and +security-hardened <>. When gpsd receives a sentence with a timestamp, it packages the received timestamp with current local time and sends it to a @@ -585,7 +588,7 @@ While gpsd may be runnable as non-root, you will get significantly better accuracy of time reporting in root mode; the difference, while almost certainly insignificant for feeding Stratum 1 time to clients over the Internet, may matter for PTP service over a LAN. Typically -Only root can access kernel PPS, whereas in non-root mode you're limited to +only root can access kernel PPS, whereas in non-root mode you're limited to plain PPS (if that feature is available). As noted in the previous section on 1PPS quality issues, this difference has performance implications. @@ -1665,6 +1668,8 @@ by Jaap Winius . - [[[NTP.ORG]]] http://www.ntp.org/[Home of the Network Time Protocol project] +- [[[NTPSEC.ORG]]] http://www.ntpsec.org/[Wecome to NTPsec] + - [[[USE-POOL]]] http://www.pool.ntp.org/en/use.html[How do I use pool.ntp.org?] - [[[CVE-2009-3563]]] http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2009-3563 @@ -1731,5 +1736,8 @@ by Jaap Winius . 2.5 Apr 2016:: Note the existence of the GR701-W. -2.6 May 2015:: +2.6 May 2016:: New section on GPS time. Note the existence of the GR801-W. + +2.7 May 2016:: + Describe the special timeserver build of GPSD. Recommend NTPsec. -- cgit v1.2.1