[ntp:questions] Re: server's address in ntp payload?

Brian Utterback brian.utterback at sun.removeme.com
Mon Nov 21 13:23:11 UTC 2005

Danny Mayer wrote:
> David Schwartz wrote:
>>"Danny Mayer" <mayer at gis.net> wrote in message 
>>news:437D4371.2090004 at gis.net...
>>>No it is not a flaw in the protocol design. It would be if it were put
>>>in. The address doesn't belong there, it belongs in the IP header which
>>>the receiving server always gets.
>>    It is a flaw. Its absence requires the receiver to assume that the 
>>origin address of the UDP packet received is the IP address of the sending 
>>server. This assumption may or may not be correct. But if the address were 
>>in there, the assumption would not be needed.
> Absolutely not. That would be a layering violation. Verification is done
> through key exchange and the MAC section in the NTP packet.

If that is a layering violation, then why do you need to know both the
source and destination address of each NTP packet to authenticate it?


"Having them stolen may become our distribution model..."
Nicolas Negroponte on the Hundred Dollar Laptop.
Brian Utterback - OP/N1 RPE, Sun Microsystems, Inc.
Ph:877-259-7345, Em:brian.utterback-at-ess-you-enn-dot-kom

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