[ntp:questions] Re: server's address in ntp payload?
David L. Mills
mills at udel.edu
Sat Nov 26 06:04:23 UTC 2005
Lets stop this. My previous message says it all. The issue about
transaction ID is fully disclosed. There will be no further input from
me on this issue. If you have substantive input, I am willing to
participate. Otherwise, I intend to get along with more important issues.
David Schwartz wrote:
> "Danny Mayer" <mayer at ntp.isc.org> wrote in message
> news:43876FE3.1010309 at ntp.isc.org...
>>David Schwartz wrote:
>>>>I would therefore contend
>>>>that a protocol
>>>>that has this requirement gratuitiously is flawed.
>>> Right, so NTP is flawed because it does not put the IP address in the
>>>payload, thus requiring you to get it from the kernel if you need it. (I
>>>don't agree with your premises, but they lead inexorably to this
>>As long as you don't receive packets on the wildcard addresses your
>>response will go out using the same address as the packet was received
>>on. It's the wildcard addresses that cause the problem and you cannot
>>know which address the kernel may choose.
> Right. RFC1123 says:
> * "SHOULD"
> This word or the adjective "RECOMMENDED" means that there
> may exist valid reasons in particular circumstances to
> ignore this item, but the full implications should be
> understood and the case carefully weighed before choosing
> a different course.
> When the local host is multihomed, a UDP-based request/response
> application SHOULD send the response with an IP source address
> that is the same as the specific destination address of the UDP
> request datagram.
> What this means is that a UDP-based request/response application must
> send responses with the source address that was the destination in the reply
> unless the full implications of not doing so are understood and the case is
> carefully weighed. Failure to do this is failure to comply with RFC1123.
> RFC1123 states the host *requirements* for being part of the Intenet.
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