[rfc-i] Drafting issue... use of MAY

Dave Thaler dthaler at microsoft.com
Tue May 1 10:22:38 PDT 2018


John Levine writes:
> I find relatively few uses for MAY, but one of them would be "letters in domain names MAY be in uppper or lower case."

Agree with the former, and disagree with the latter.  Example of ok usage would be something like:
"letters in domain names SHOULD be in lower case, but MAY instead be in upper case".

MAY means it's optional and you can choose not to do it.  You can't choose not to have letters be in upper or lower case, you have to pick one of the two.  You might argue they "MUST be in upper or lower case", but that would be inappropriate in my view also since it's not possible to violate the MUST, and it's not possible to test it since there's no way to fail the MUST.

If there's two options, each of which is equally acceptable and neither is recommended, then a simple "can" would suffice instead of "MAY".

Dave


More information about the rfc-interest mailing list