Re: After a 450, queue or try next MX?
2006-08-30 12:07:40
Folks,
Tony Finch wrote:
On Wed, 30 Aug 2006, Alex van den Bogaerdt wrote:
Where does it say the client should stop trying after a 5xx message?
And I mean stop trying the entire list, not just that one host?
4.2.1 Reply Code Severities and Theory
5yz Permanent Negative Completion reply
The command was not accepted and the requested action did not
occur. The SMTP client is discouraged from repeating the exact
request (in the same sequence).
i.e. the same seqence of commands, regardless of destination host.
"regardless of destination host" might be a reasonable decision, but I
certainly do not see it implied by the language of the specification.
More importantly, this thread demonstrates that there are a variety of
reasonable -- if conflicting -- choices to be made. So, the
specifications are not going to impart divine wisdom.
At that point, the discussion ought to be about what is the most
productive choice for the originator and the recipient.
On reflection, my own opinion is that the model of using an MX when a
connection fails makes sense. If an SMTP connection is established,
then a server has stepped forward to participate. The client should
pursue matters with that server, unless and until that server drops out.
A 4xx response does not constitute dropping out.
Hence, a 4xx response strikes me as warranting a later try, either
directly with that same host, or with a fresh DNS query.
d/
--
Dave Crocker
Brandenburg InternetWorking
bbiw.net
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- After a 450, queue or try next MX?, Michael Kenny
- Re: After a 450, queue or try next MX?, Eric A. Hall
- Re: After a 450, queue or try next MX?, Alex van den Bogaerdt
- Re: After a 450, queue or try next MX?, Tony Finch
- Re: After a 450, queue or try next MX?, Eric A. Hall
- Re: After a 450, queue or try next MX?, Alex van den Bogaerdt
- Re: After a 450, queue or try next MX?, Tony Finch
- Re: After a 450, queue or try next MX?,
Dave Crocker <=
- Re: After a 450, queue or try next MX?, Alex van den Bogaerdt
- Re: After a 450, queue or try next MX?, Hector Santos
- Re: After a 450, queue or try next MX?, Alex van den Bogaerdt
- Re: After a 450, queue or try next MX?, ned+ietf-smtp
- Re: After a 450, queue or try next MX?, Hector Santos
- Re: After a 450, queue or try next MX?, ned+ietf-smtp
- Re: After a 450, queue or try next MX?, Eric A. Hall
- Re: After a 450, queue or try next MX?, Hector Santos
- Re: After a 450, queue or try next MX?, Paul Smith
Re: After a 450, queue or try next MX?, Hector Santos
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