> On Feb 3, 2017, at 2:38 PM, Wei Chuang <weihaw@xxxxxxxxxx> wrote: > > Can you clarify what this means for addresses such as: > > U: ietf-dane@духовный.org > > Not recommended but supported by SmtpUtf8Name. > > > A: ietf-dane@xxxxxxxxxxxxxxxxxxxx > > Use rfc822Name. This is recommended. So, to be clear, for the same domain, some addresses will be represented as rfc822Name SAN elements (with the domain in A-label form), and other addresses (those with non-ASCII localparts) will be represented as SmtpUtf8Name SAN elements (with the domain in U-label form). A verifier checking for an address with a non-ASCII localpart will compare against SmtpUtf8Name elements with U-label domain encodings, while a verifier checking for an address with an all ASCII localpart will check against rfc822Name elements using an A-label domain encoding (of the same domain). Is that right? Thus the verifier would sometimes need to convert from U-labels to A-labels (when the localpart is all ASCII), and at other times from A-labels to U-labels (when the localpart is not all ASCII)... -- Viktor.