[ntp:questions] Meinberg NTP Software--Time Accuracy

Todd Glassey CISM CIFI tglassey at earthlink.net
Mon Jun 29 01:11:10 UTC 2009

Danny Mayer wrote:
> tglassey wrote:
>> Danny Mayer wrote:
>>>>>> By geography, just like the zones that were mentioned in the post
>>>>>> above.
>>>>>> However, they are more fine-grained, especially when compared with
>>>>>> large zones like us or eu.
>>>>> How are you going to know the geography. DNS clients does not supply
>>>>> that information even if they knew it and it's certainly not part of
>>>>> the
>>>>> DNS protocol.
>>>> Danny isnt the location data potentially available as part of HOST
>>>> listings and Location Records?
>>> What Host listings and Location Records? There are no such types
>>> available in DNS and even if they were they would not be local to the
>>> nameserver responding. In any case such records would be entirely
>>> voluntary, ie never added to a nameserver anywhere.
>> Ah, let me be clearer -  I didn't say lots of people were using it, and
>> it is as well as defining Well Known Services. As it happens though
>> there are some folks who do use these. Especially true with some of the
>> military BF (battle field)  process equipment.
> This makes no sense. The are no such types and so they cannot be used
> even if they existed. Furthermore the only entry in the request is the
> name for which an address is requested. The client does not even send
> the request directly to the authoritative server. It makes a request via
> a resolving server and that is the server that contacts the
> authoritative server. The authoritative server has no knowledge
> whatsoever not only of the client but what it intends to do with the
> returned addresses.
Right - explain that to Vix will ya? - http://tools.ietf.org/html/rfc1876
> As for Well Known Services I assume you are talking about SRV records
You mean RFC2782 specfied SRV records - sure they work but so do the 
legacy Location Records and the WKS1035) can have this data in them as well.
> but those don't even come into the picture here. BF process equipment
> don't use DNS for this kind of stuff. 

Here is one of many papers on location specific information in DNS - 

> I suggest you pick up a good book
> on DNS so you can understand how this works. DNS and BIND by Cricket Liu
> is the usual recommendation...
Thanks I have two copies of it (Editions 1 and 2).

> Danny
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