Empty domain-spec on exp modifier
Section 6.2/4 says:
If domain-spec is empty, or there are any DNS processing errors (any RCODE
other than 0), or if no records are returned, or if more than one record
is returned, or if there are syntax errors in the explanation string, then
proceed as if no exp modifier was given.
However, 6.2/1 gives the grammar for exp as:
explanation = "exp" "=" domain-spec
domain-spec = macro-string domain-end
domain-end = ( "." toplabel [ "." ] ) / macro-expand
Thus, domain-spec can never be empty. Syntax errors require a permerror
result, which conflicts with the instruct to "proceed as if no exp
modifier was given."
Therefore, the grammar for exp should be:
explanation = "exp" "=" [ domain-spec ]
Rationale:
Unknown-modifier is defined as:
unknown-modifier = name "=" macro-string
This means that implementations not supporting the exp modifier would not
give a permerror. Unlike redirect, the exp modifier is not critical, so
giving permerror for an otherwise valid record is counter productive.
--
Stuart D. Gathman <stuart(_at_)bmsi(_dot_)com>
Business Management Systems Inc. Phone: 703 591-0911 Fax: 703 591-6154
"Confutatis maledictis, flammis acribus addictis" - background song for
a Microsoft sponsored "Where do you want to go from here?" commercial.
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