[ntp:questions] Bad NTP servers jeopardizing the pool.ntp.org initiative

Jan Ceuleers janspam.ceuleers at skynet.be
Sat Mar 31 08:38:20 UTC 2007


Danny Mayer wrote:
> Jan Ceuleers wrote:
>> (I suggested that pool members with non-static IP addresses could be 
>> accommodated by the pool).
> 
> Well you shouldn't have. It just won't work for any useful time period.

Well excuse me for thinking out loud...

As you might have seen elsewhere I do agree that this is only a good 
idea under well defined circumstances, and I would now add that it is 
difficult to ascertain up-front whether these conditions are met (i.e. 
whether it would be desirable for a particular NTP server on a dynamic 
IP address to be admitted to the pool).

>> Advantages: dynamic DNS clients exist for lots of platforms.
> 
> Clients yes, servers no. The pool is a bunch of *servers* not clients so
> why are you talking about the clients?

Because the pool members are NTP servers, but under my scheme would be 
clients of the pool dynamic DNS service (in that they register their 
current IP address with the pool). Users of the pool would be ordinary 
DNS clients (in that they send ordinary DNS queries via their DNS 
infrastructure which would ultimately be resolved by the pool 
infrastructure servers), in addition to being NTP clients.

>> The other disadvantage is that pool clients might, for a limited period 
>> of time, hammer whoever next receives the IP address previously held by 
>> a pool server. Malevolant such inherintants of IP addresses might reduce 
>> the perceived quality of the pool by telling the wrong time.
> 
> No, this isn't a limited length of time it's a long time, possibly
> months until it ceases and even then maybe not. You should not be
> guessing at the longevity of the provided IP address providing NTP service.

Please remember that I started this suggestion in the context of a 
discussion of code being added to ntpd that re-resolves server addresses 
in case of non-reachability. Such code, _if deployed on a critical mass 
of clients_ (i.e. optimistically, not for a good few years) would 
address your concern (while not completely removing it).

> Danny

Danny, please can you be a little less curmudgeonite? You have valuable 
contributions to make, if only you made them less abrasively...

Jan




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