Can an email address contain international (non-english) characters?

Question

If it's possible, should I accept such emails from users and what problems to expect when I will be sending mails to such addresses?

Answer 1

Experimentally, per RFC 5355 - Yes.

For a quick explanation, check out wikipedia on the subject.

Answer 2

Not yet. The IEEE plans to do this: H-Online article: IEFT planning internationalised email addresses

Answer 3

I would assume yes since a number of top level domains already allow non ascii characters for domains and since the domain is part of an email address, it's perfectly possible. An example for such a domain would be www.öko.de

Answer 4

short answer: yes

not only in the username but also in the domain name are allowed.

Answer 5

The problem is that some mail clients (server-tools and / or desktop tools) don't support it and throw an 'invalid email' exception when you try to send a mail to an address which contains umlauts for example.

If you want full support, you could do the trick with converting the email-address parts to "punycode". This allows users to type in their addresses the usual way but you save it the supported-level way.

Example: müller.com » xn--mller-kva.com

Both points to the same thing.

Answer 6

The answer is yes, but they need to be encoded specially.

Look at this. Read the part that refers to email-headers and RFC 2047.