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Re: rfc2821bis-07

2008-02-21 11:18:49

Derek J. Balling wrote:

On Feb 21, 2008, at 11:16 AM, Tony Hansen wrote:
 The result of an MX lookup MUST NOT be a

I still say that verbiage, wherever it is, will be unnecessarily confusing. If a lookup for "the MX of a domain" yields a CNAME RR, then it could be said that the MX lookup was a CNAME, and that's *not* what is being proscribed against.

That above sentence needs to be reworded to actually be syntactically correct, IMHO.


+1, especially since the DNS client performing a MX lookup will resolve the CNAME and that that overall request would not result in a CNAME for SMTP MX expansions. It essence, the semantics seem to be more appropriately applied as a reminder to DNS clients doing a MX request in general.

I actually recall seeing this before but decided it wasn't worth the aggravation. After all, it isn't the current SMTP vendors problem. They are doing it right and future SMTP vendors/clients who decide to roll their own DNS Client will find out the hard way that a CNAME is part of the MX expansion process. But if they use a DNS client API, these library already figured it out. It will be transparent to the SMTP client using a DNS client API.


Hector Santos, CTO