SMTP extension for internationalized email address

Document Type Expired Internet-Draft (individual)
Authors XiaoDong Lee  , Jiankang Yao 
Last updated 2006-02-28
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


Internationalized eMail Address (IMA) includes two parts, the local part and the domain part. The way email addresses are used by protocols are different from the way domain names are used. The most critical difference is that emails are delivered through a chain of peering clients and servers while domain names are resolved by name servers by looking up their own tables. In addition to this, email transport protocols SMTP and ESMTP provide a negotiation mechanism through which clients can make decisions for further processing. So IMA is different from the internationalized domain name (IDN). IMA can be solved by exploiting the negotiation mechanism while IDN can not use the negotiation mechanism. So IMA should be solved in the mail transport-level using the negotiation mechanism, which is an architecturally desirable approach. This document specifies the use of SMTP extension for IMA delivery. It also mentions the backward compatible mechanism for downgrade procedure, as specified in an associated specification. The protocol proposed here is MTA-level solution which is feasible, architecturally more elegant, and not as difficult to deploy in relevant communities.


XiaoDong Lee (
Jiankang Yao (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)