[ntp:questions] Re: "Listen on" semantics

Danny Mayer mayer at ntp.isc.org
Sun Sep 24 03:34:27 UTC 2006


Maarten Wiltink wrote:
> At this point, people will shriek 'that's an SNTP server! Not NTP!' But
> is it? What's the difference? The current definition seems to be that
> to be an NTP server, you have to implement the client functionality (the
> math) yourself. I think it's more important _that_ the math is being
> done. _Where_ is not that important.
> 

No, that's not true. The receiving end MUST be the one doing the math.
There is no way for the server to know what the delays are in getting a
packet to the client. Only the client has a chance to know that.

> 
> [...]
>> OpenBSD's OpenNTP was, as I recall (and IMO), originally a malignantly
>> broken SNTP implementation.
> 
> Malignantly, no less? Come off it. Sure, they made mistakes, but that
> wasn't the intent. The intent was to build something with no exploits.
> If the question is what comes first, working right or not getting rooted,
> well, they _are_ OpenBSD.

Which means absolutely nothing. People don't set up to create buggy or
exploitable code. I don't assume that just because they've given
themselves a label that they have an automatic level of trust in their
software. On top of that even if the code is not exploitable it doesn't
mean that it's correct.

> 
> (Wouldn't a client-mode real NTP, combined with an OpenSNTP server, be
> the ideal configuration?)
> 

No.

Danny

> Groetjes,
> Maarten Wiltink



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