[ntp:questions] NIST vs. pool.ntp.org ?
no-one at notreal.invalid
Wed Mar 27 19:20:00 UTC 2013
I am confused about the proper usage of pool.ntp.org and NIST.
pool.ntp.org seems to be a collection of private sector time servers
offered for all to use, but with registration expected for regular
users. And NIST has a government run set of time servers. Neither
group (NIST or pool.ntp.org) seems to include or referece the other.
Are they in competition? Who normally uses the NIST servers and who
I posted here several months ago about my specific application. I
want to use SNTP, not to synchronize a system clock but to make a
frequency measurement on the audio sampling rate in a smartphone. My
use of time servers will be very occasional - typically a user of my
app would only use the time servers once when the app is first
installed to do a calibration of the audio sampling rate in that
phone. And my app will have very limited circulation. So I won't be
hitting the servers very often at all.
Today I found the last bug that prevented me from getting response
from the time servers in my socket code. I had neglected to set the
port number (123) using htons(123) to put the port number in network
byte order. When I fixed that I finally started getting responses.
I have gotten responses from pool.ntp.org as well as several of the
NIST time servers listed on their website. However the round-robin
address of time.nist.gov does not seem to return anything. The recv()
function just times out. And I sure don't want to hard-code any of
the other NIST server URLs in my app. I was going to go with
pool.ntp.org until I saw the NIST servers that did not seem to be part
of the pool.
So I guess my main question is which servers should I use for my very
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