[ntp:questions] ntpdate.c unsafe buffer write

David Woolley david at ex.djwhome.demon.co.uk.invalid
Tue Feb 12 22:36:23 UTC 2008

Unruh wrote:
> David Woolley <david at ex.djwhome.demon.co.uk.invalid> writes:
>> Harlan Stenn wrote:
>>> For the general use case (LAN and/or WAN and/or jerky path) ntpd behaves
>>> well.
>> We are talking typical rather than general cases.  In the typical case, 
>> 1ms after 1 second is a reasonable expectation on a WAN, especially when 
>> a site is restarting, e.g. after a power failure, or a home system 
>> switching on, and, therefore, the network load is low.
> I think you go t your units mixed up. computer A goes down for three days
> due to an avalanch cutting the power. It takes a lot longer than one second
> to resync that computer. A few hours is more like it. 

I was talking about what people could expect from software that behaved 
well; I think you are describing what ntpd actually does here.  My point 
was that ntpd's ability to tolerate really rotten links is irrelevant 
for most users, who are only about 20ms away from their ISP's time 
server, and can expect to read it to about 1ms accuracy.

> If you mean, I shut down ntp and restart it immediately , then 1ms in 1
> minute is reasonable ( you cannot have made enough measurements in 1 sec to
> even know if it is accurate.)

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