On Fri, Jun 08, 2007 at 07:03:48AM -0700, Douglas Otis wrote:
On Jun 8, 2007, at 1:59 AM, Charles Lindsey wrote:
On Thu, 07 Jun 2007 14:41:22 +0100, Hector Santos
<hsantos(_at_)santronics(_dot_)com> wrote:
Charles Lindsey wrote:
In other words, not all MX query gives you IP addresses to try.
So in that case, you can have an MX that directs you to the
domain nomail.invalid (which has no A record, of course) and
that is the end of the matter. What is wrong with that?
A change in long establish SMTP semantics and sending strategies.
No. Just a way to say this domain does not want to receive any
email, even though it has an A record. That MX should get cached
(so no excessive load on the authoritative server). And
nomail.invalid should also get cached, as a DNS failure, or so I
have been informed, so no excessive load on the root servers; a
smart DNS resolver will already have built into it that 'invalid'
is not even worth looking up. I proposed it as an alternative to
the suggested "MX .", which apparently had problems.
This is a different name with a worse problem. An MTA is unlikely to
know that either "." or "nomail.invalid" is an invalid host name.
I didn't think they were proposing any particular name, just that after
looking up the MX record, the corresponding A lookup failed. Surely all
MTAs should be able to handle that case. Newer ones would realize that
the domain in question doesn't want any mail, while older ones may
retry till the message expires.
--
:: Jeff Macdonald | Principal Engineer, Messaging Technologies
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