Can punycode-encoded email addresses clash with "real" addresses?
The problem is this: I'm using a third-party Email delivery service that doesn't accept mail addresses with non-ASCII characters in the name part, like mü[email protected] .
Encoding such an address with Punycode:
http://en.wikipedia.org/wiki/Punycode
yields this address:
And sending mail to it via the service seems to work.
However, I'm not sure if someone couldn't register "[email protected]" directly, thus receiving Emails meant for "mü[email protected]".
Is this clashing possible ? Are there other solutions for this problem ?
UPDATE
Thanks for the answers. Here's a summary of what we learned:
- Punycoding the local part of the email address works, and you can send and receive from such an encoded address (of course)
- However, there are no guarantees at all that providers or mail clients will understand the encoding, or do it automatically. Clashes are therefore possible, and the whole idea not a good one :)
- One should simply do what everyone else does, which is to not allow or accept non-ASCII name parts, as per specification
- And finally, it turns out the third-party service prohibits such shenanigans anyway.
Answer
Non-ASCII characters are not allowed in the local part of email addresses. Period. Punycode is ONLY FOR DOMAINS, not for local parts of email addresses.
However, it is very likely that the IETF adopts a standard that makes internationalized local parts possible. This standard, however, will probably not be based on punycode.