Clarifying, since this question comes up from time to time: Also note that only the initial sender can do this. If mail goes A->B->C, A can downgrade if the A->B hop can't do EAI, but B cannot if B->C can't Is this a MUST or a SHOULD (recognizing that RFC-style SHOULD is still very firm)? /marksv -----Original Message----- From: ua-eai-bounces@icann.org [mailto:ua-eai-bounces@icann.org] On Behalf Of John Levine Sent: Saturday, November 4, 2017 7:21 PM To: Don Hollander <don.hollander@icann.org> Cc: ua-eai@icann.org Subject: Re: [UA-EAI] Thoughts on Downgrading On Fri, 3 Nov 2017, Don Hollander wrote:
The UASG will (after further consultation) include the following as a Good Practice (not best practice) guide for Downgrading:
- The EAI Mailbox provider establishes an EAI address and an ASCII alias when the mailbox is set up.
- The ASCII alias will have a display name equal to the EAI Address.
- When a non-EAI compliant mail system is encountered, the EAI MTA will revert with the ASCII alias and Display Name.
- The ASCII Alias should not default to a Punycode conversion of the mailbox name because bi-directional equivalence cannot be guaranteed.
Also note that only the initial sender can do this. If mail goes A->B->C, A can downgrade if the A->B hop can't do EAI, but B cannot if B->C can't. Regards, John Levine, john.levine@standcore.com<mailto:john.levine@standcore.com> Standcore LLC _______________________________________________ UA-EAI mailing list UA-EAI@icann.org<mailto:UA-EAI@icann.org> https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmm.icann.or...