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

David Schwartz davids at webmaster.com
Wed Nov 23 18:06:50 UTC 2005

"Brian Utterback" <brian.utterback at sun.removeme.com> wrote in message 
news:4384A438.6050108 at sun.removeme.com...

> This brings up a an interesting question. Is there anywhere in any of
> the published or proposed RFC's related to NTP that explicitly states
> that NTP requires that the response packet have the same IP source
> address as that of the original request packet's destination address?
> Or is that merely an artifact of the reference implementation? I
> know that the protocol will fail if the addresses do not match, so
> there is an implicit requirement, but it ever explicitly stated?

    I think if you can make the argument that the source address doesn't 
have to match the destination of the query, you can equally well argue that 
the destination address doesn't have to match the source of the query. ;)

    Or, to put it another way, as soon as you layer a request/reply protocol 
on top of UDP, the default presumption would be that the reply MUST have the 
same source as the query's destination and vice-versa.


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