[DNSOP] draft-ietf-dnsop-integration text on ASCII-or-not

[Ben Schwartz <[e-mail]>]

Current text:

   DNS integrations should also be aware that global DNS domain names
   are not limited to ASCII characters, e.g., as described in [RFC5890].
   DNS integrations should also be aware that the list of valid global
   DNS TLDs can change, so should not hard code a list of accepted TLDs.
   If applications want a list of currently valid TLDs, they can use a
   routinely updated list of public suffixes such as that provided by
   IANA [IANA-PSL].  Failure to account for such domain names may lead
   to inadvertent exclusion which could also lead to registrant and user
   confusion.

My proposed text:

   DNS integrations should be aware that the list of valid global
   DNS TLDs can change, so should not hard code a list of accepted TLDs.
   If applications want a list of currently valid TLDs, they can use a
   routinely updated list of public suffixes such as that provided by
   IANA [IANA-PSL]. Failure to account for new TLDs may lead
   to inadvertent exclusion which could also lead to registrant and user
   confusion.

   When interacting with non-technical users, applications should present and
   accept domain names in Unicode "u-label" format [RFC5890].
   Special care must be taken to avoid homograph attacks in the user interface.
   In the DNS wire format, applications should only use domain names that
   conform to the "Preferred Name Syntax" [RFC1123] or the Attrleaf
syntax [RFC8553].
   Domain names in wire-format should be checked for non-compliant
characters (e.g.
   labels containing ".", uppercase, whitespace, or non-ASCII characters) due to
   security risks.

--Ben Schwartz