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Re: MX to CNAME and (mis)interptretation of 2821

2007-12-13 05:53:39

At 00:08 13/12/2007, Hector Santos wrote:


Who is right or wrong is a matter of historical perspective.

The fact is this:

All current/modern DNS clients will support the resolution of a CNAME as part of a MX expansion process.

No. That should be '_Many_ current/modern...' or even '_Most_...', but to say 'All' is presumptive.

RFC 2821 definitely doesn't allow CNAMEs as the bit that the MX is pointing to. It does allow it as the bit it's pointing _from_, but that's different.

Just because many people have written their software that works around bugs in some DNS configurations doesn't mean that those buggy DNS configurations are right.

Given that it would take about 2 minutes for TrendMicro to fix their DNS configuration, I really don't see what the fuss is about from their POV. They're wrong. Everyone else is right to complain. If TrendMicro hadn't been told about the problem, their configuration would be understandable, but now it just seems like stubbornness. In the time they took to write their knowledgebase article explaining why they're doing wrong, they could have fixed the problem 10 times over.

They even admit that some older software may not work with their DNS configuration - but it would be trivial to fix it, so why don't they???

RFC 2181 isn't updated or obsoleted by RFC 2821, so it still applies today.