[ntp:questions] Clock time synchronization of four computers

unruh unruh at invalid.ca
Mon Jul 9 04:24:52 UTC 2012


On 2012-07-08, Nazmul Islam <nazmul.islam at gmail.com> wrote:
>>
>> Hello,
>>
>> I have not used ntp processing before. I apologize in advance if my
>> questions seem too novice.
>>
>> I am trying to synchronize the clocks of four computers. The timing does
>> not have to be accurate but they have to be sync'd with each other.  An
>> error tolerance of 10-20 ms is acceptable. The computers are connected to
>> the servers.

Well a good way of synchronizing them is to have them all synchronized
to UTC. Another is to synchronize one to UTC and the others to it as the
server.

>>
>> I installed ntp by typing 'sudo apt-get install ntp' in the terminal. When
>> I typed "sudo ntpq -c lpeer", each computer was found to be connected to
>> different timing websites.

So what?
They are all probably pool servers and synchronized to UTC. But if you
want something else, edit /etc/ntp.conf and put in the same "server"
lines.


>
>    Therefore, I modified the ntp.conf server list and put the following
> ones for each of them (I am at NJ, USA):
>
> server nist1-ny.ustiming.org
> server nist1-nj.ustiming.org

Why would you overload a level 1 server?

> server ntp.ubuntu.com
>
>
>> However, each computer is still off. It's hard to find the exact time
>> difference from eye-balling but I can see a clock time difference of
>> roughly 1-2 second.

No idea what that means, but on each of them use ntpq to look at the
time offset from utc.

You do not tell us what operating system you are using. 
ssh other.computer date;date
will tell you if they are off by seconds. 


>>
>> What should I do to synchronize these computers?



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