[ntp:questions] NTPD concurrent clients limit

David L. Mills mills at udel.edu
Thu Aug 14 17:05:56 UTC 2008


Guys,

Please, please and more please, read the Rate Management and the 
Kiss-o'-Death page (rate.html) in the online documentation before 
continuiong this thread.

Dave

Unruh wrote:
> hal-usenet at ip-64-139-1-69.sjc.megapath.net (Hal Murray) writes:
> 
> 
> 
>>>His question can be rephrased, what does ntpd do after it has sent the Kiss of Death?
>>>does it drop all subsequent packets? -- That sounds like a huge cost on the
>>>ntp server-- ie imagine a popular server with 10,000 machines it has sent
>>>the KoD to. It then has to scan that whole list for each packet to see if
>>>it is in there-- something which takes time and destroys the ability of ntp
>>>to deliver its time base rapidly.
> 
> 
>>A hash table would solve that problem.  (assuming you wanted to
>>keep track of many many clients)
> 
> 
> I think the question is what ntpd does, not what it could do. 
> 
> 
> 
>>Note also that scanning a long list won't destroy the accuracy.
>>NTP uses 2 time stamps, one when the packet arrives and one
>>when the packet exits.  In between you can do all sorts of things,
>>for example crunch away for a while doing crypto stuff.
> 
> 
> 




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