[ntp:questions] "No association ID's returned" after a period of time

Martin Burnicki martin.burnicki at meinberg.de
Fri Dec 19 08:40:39 UTC 2014

Phil W Lee wrote:
> Martin Burnicki <martin.burnicki at meinberg.de> considered Thu, 18 Dec
> 2014 14:43:08 +0100 the perfect time to write:
>> saxenaakash90 at gmail.com wrote:
>>> hello all,
>>> please help me in configuring broadcast ntp server and client.
>>> I have configured NTP version 4.2.6 server on fedora 20 machine. server side I am using local system time and given a broadcast subnet and all other options are disabled and on client's side I enabled only broadcast client. I haven't given server's address as according to my understanding server should broadcast NTP packets and client will automatically listen NTP packets and will get sync. but my NTP client is not syncing with server. please help me with all possibilities.
>> broadcast is not the default mode of operation with ntpd. You have to
>> configure it explicitly both on the client *and* on the server.
>> Also, you need to configure symmetric keys or autokey explicitely to
>> prevent your client from accepting *every* NTP broadcast packet seen on
>> your network, or explicitly disable authentication.
>> In broadcast mode the client is unable to determine and compensate the
>> network packet delay properly, so this usually yield only less accuracy
>> than normal client/server mode.
>> If you are new to NTP you should start with the default mode of
>> operation, i.e. client/server mode. If you have an NTP server on your
>> network just add an appropriate "server" line to the client's ntp.conf
>> file. For example
>> server 111.222.333.444 iburst
>> if your NTP server has IP address 111.222.333.444.
>> Is your NTP server synchronized to some other time source? If it is not
>> then your NTP server will not be accepted by any real NTP client.
> Unless you fudge it to give the local clock a high stratum, surely?

*If* you have the local clock configured on your NTP server.

> Not really a very good idea, but could be of use in a time island
> which only needs to be consistent with itself.

There are some scenarios where using the local clock with good stratum 
on an NTP server makes sense. However, for a beginner with NTP it should 
be important to know that in general a server needs to be synchronized 
to some source, or clients will ignore it.

Yet there hasn't been another comment from the OP.


More information about the questions mailing list