Re: [enum-wg] ENUM-capable email client?

* John C. Klensin:

permitting, e.g., +12345678901234

as an email address would require changing of every MTA in the network before ENUM->email would work reliably. Such agreement is unlikely. For example, +12345678901234@example.com could be a valid email address today, having nothing to do with ENUM.

You would use +12345678901234@e164.arpa, I guess, where the @e164.arpa part could be supplied by the MUA. (Of course, e164.arpa should have a "MX ." RR.) If you opt for a purely MUA-based approach, you can never-ever put E.164 addresses in the message header. ENUM email addresses would remain second-class citizens, just like internationalized domain names implemented with IDNA.