[ntp:questions] NTPD concurrent clients limit

Unruh unruh-spam at physics.ubc.ca
Thu Aug 14 04:19:47 UTC 2008


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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