[Mailman-Developers] What characters should be allowed in listnames

[SM]

Hi Stephen,
At 10:12 PM 2/18/2017, Stephen J. Turnbull wrote:
>The problem that I thought we may face is internationalized mailboxes
>and domain names *are still ASCII* which encodes Unicode.
>
>OK, I looked it up, and I was almost certainly wrong.  The relevant
>RFCs are actually 6531 (SMTPUTF8 extension), 5890 (IDNA), and 3492
>(Punycode).  IDNA allows "U-labels" (UTF-8), which we can gracefully
>extend to, and "A-labels" (encoded using Punycode, which uses the
>ASCII repertoire).  AFAICT (haven't really looked carefully), Punycode
>uses only letters, digits, and the hyphen ("-").
>
>So I withdraw the comment.

RFC 5890 can be used for the domain name part.  The issue would be 
about what to do for the local part.  If I recall correctly, the 
question was not discussed as part of RFC 6531.  I suggest taking a 
look at RFC 7564.

Regards,
-sm