At 00:57 26-03-2008, Mark Andrews wrote:
Which is not documented in any RFC despite being a good idea.
It is easy to turn "MX 0 ." into "This domain doesn't support
email" as "." is not confusable with a hostname. There is no
reason to look up addresses records for "."
There was an I-D, draft-delany-nullmx-00, which didn't make it to RFC status.
Which could just be a misconfiguration. You still have to
look up addresses for "dev.null".
Yes. People still do it.
If the implicit MX rule is depreciated for IPv6, the above won't be needed.
It's still needed to prevent the A lookup.
It would be needed until IPv6 takes over.
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