Is it possible to use double @ in an email address?

Question

I know Yahoo and Gmail do not accept it. But I want to know if it's possible for a person to create an email address with double @ in address and if they can receive emails with that address?

For example: [email protected]@example.com.

I do not want to use this non standard format, but I want to know if a hacker can do it?

Answer 1

According to the wiki, it is allowed.

Space and special characters "(),:;<>@[\] are allowed with restrictions (they are only allowed inside a quoted string, as described in the paragraph below, and in addition, a backslash or double-quote must be preceded by a backslash).

Answer 2

No it is not allowed. See the RFC Section 3.4.1

An addr-spec is a specific Internet identifier that contains a locally interpreted string followed by the at-sign character ("@", ASCII value 64) followed by an Internet domain. The locally interpreted string is either a quoted-string or a dot-atom. If the string can be represented as a dot-atom (that is, it contains no characters other than atext characters or "." surrounded by atext characters), then the dot-atom form SHOULD be used and the quoted- string form SHOULD NOT be used. Comments and folding white space SHOULD NOT be used around the "@" in the addr-spec.