E-mail address
An e-mail address identifies a location to which e-mail can be delivered. A modern Internet e-mail address is a string of the form jsmith@domain.example. It should be read as "jsmith at domain dot example". The part before the @ sign is the local part of the address, often the username of the recipient, and the part after the @ sign is a domain name which can be looked up in the Domain Name System to find the mail exchange servers accepting e-mail for that address.
The format of Internet e-mail addresses is defined in RFC 2822. This standard permits only a subset of ASCII characters in e-mail addresses. RFC 1642 defines UTF-7, a way of encoding all Unicode characters using only characters permitted in e-mail. E-mail addresses using this standard are most commonly seen in Asia and not widely used in Europe or North America.
Addresses found in the headers of e-mail should not be considered authoritative, because SMTP has no mechanism for authentication. Forged e-mail addresses are often seen in spam. If authentication is required, messages must be digitally signed.
See also
References
- RFC 1642: UTF-7: A Mail-Safe Transformation Format of Unicode
- RFC 2822: Internet Message Format
