[ntp:questions] SNTP server + ntpd 4.2.4 client

Unruh unruh-spam at physics.ubc.ca
Sat Mar 22 19:01:05 UTC 2008


"Richard B. Gilbert" <rgilbert88 at comcast.net> writes:

>Danny Mayer wrote:
>> Harlan Stenn wrote:
>> 
>>>David> NTP clients must use NTP servers, not SNTP ones.
>>>
>>>I do not believe this is true.
>>>
>> 
>> 
>> Correct.
>> 
>> 
>>>The problem is one might want to *know* that the SNTP server is actually
>>>talking to a refclock, or more generally, that the SNTP "instance" is
>>>playing by the rules.
>>>
>> 
>> 
>> There is no way to ensure that. Furthermore there is nothing in the 
>> protocol which allows you to differentiate between the two. This is 
>> really a non-starter.
>> 
>> Danny

>I can't say it's worth doing but you could always add some sort of a tag 
>to the NTP packet that says "I am an NTP server" or "I am an SNTP Server 
>with a reference clock" or "I am an SNTP leaf node and I'm not supposed 
>to talk to you"

Look, an SNTP client is not supposed to act as a server. Period. If it does
it means whoever programmed it broke the rules. Do you really thing having
him program in an extra flag saying "I did not break the rules" is going to
do anything? It is the same person who programmed it in the first place who
also programs what it sends out in the packet.  
An sntp client is not supposed to respond to server requests. You want it
to respond. Why? I would think that the "flag" of no-response is far more
effective than some bit in the packet.




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