Re: I-D ACTION:draft-hoffman-utf8headers-00.txt

> Sure. I've seen such code code convert
>
> To: [email protected]
> To: [email protected]
>
> into
>
> To: [email protected], [email protected]
>
> I don't think it's a problem. The former is illegal to start with 
> IIRC, so forwarding it unchanged is just as illegal as forwarding it 
> changed.

nope, that's bad layering.  the job of an MTA is to forward each 
message intact, not to potentially change every message so that the 
message it forwards is correct syntax.  the latter behavior is much 
more error prone as the code that detects and corrects errors may be 
buggy, and often errors cannot be corrected without resorting to 
unreliable heuristics.  it also makes it much harder to upgrade the 
message format.  imagine what happens when utf-8 headers leak (as they 
inevitably will) into an MTA that tries to insist that all headers on 
messages that it forwards are 7bit only.  the output is not likely to 
be usable even if it is valid syntax.

we do recognize that there are some conversions and gateway operations 
that require well-formed input in order to produce well-formed output. 
such conversions are occasionally necessary but should be avoided when 
possible.