[ntp:questions] Re: uk pool problem

David L. Mills mills at udel.edu
Wed Sep 6 13:54:18 UTC 2006


David,

Academic or not, the source port was specified as 123 in order to make 
symmetric modes (active and passive) work. The operative NTPv4 
specification says the source port in other modes can be anything.

Dave

David Woolley wrote:
> In article <44FA1F44.6080305 at ntp.isc.org>,
> mayer at ntp.isc.org (Danny Mayer) wrote:
> 
> 
>>As I recall, the protocol requires that the source port be 123 but the
> 
> 
> There is one mention of 123 in RFC 1305, but several places where it
> says that the response is sent to the actual source port (RFC 1305 is
> an atypical RFC, being written as an academic research paper, and that
> sort of detail seems to be peripheral to the main, maths, content).
> 
> 
>>ntpd reference server implementation does not enforce that. I don't
> 
> 
> For several years now, it has been almost essential that it does respond
> to client requests from other ports, because of network address translation.
> 




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