[ntp:questions] ntpdate.c unsafe buffer write

Tom Smith smith at cag.zko.hp.com
Sat Feb 9 12:41:54 UTC 2008

Richard B. Gilbert wrote:
> David Woolley wrote:
>> David L. Mills wrote:
>>> Harlan,
>>> You make some good points. However, if folks want SNTP from here I 
>>> think they would prefer it in its own distribution rather than bundle 
>>> it with the huge NTP distribution. You can make a strong argument to 
>>> host here 
>> I don't think you are ever going to get rid of ntpdate from the 
>> distribution (as supplied by packagers and vendors) until ntpd offers 
>> a mode which sets the time within about one second of being started.  
>> I'm not convinced that SNTP will displace ntpdate for this purpose.  
>> People don't want to delay boot sequences, but they also don't want to 
>> start applications until the time has been set.
> How long does "ntpd -g" take to set the time?  As I understand it, it's 
> supposed to query the configured servers, make a "best guess" as to what 
> time it is, set that, and then go to normal operation.
> That should put you within a second or so.  If you need better, either 
> wait for it, or keep your server alive 24x7x365.  I think most data 
> centers do run 24x7x365.  If you're talking about a "data center" that 
> lives under the boss's desk, consider buying a UPS and hope that the 
> power doesn't fail for longer than the run time.

David is right.

He means be done with it, including hard-setting the clock, within a second.
The accuracy expected, based on "ntpdate -b" as the benchmark you are trying to
replace, is within a small number of milliseconds of the specified servers.

Sorry, "ntpd -q" doesn't meet the requirements.


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