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

Danny Mayer mayer at gis.net
Sun Nov 20 17:16:22 UTC 2005

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.

>     DS

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