What is an Email Address?

About

An email address is a Internet identifier for:

in a SMTP transaction
- an email sender
- a recipient (inbox)
in a email message
- a to header address
- a from header address
- a cc header address
- a bcc header address

The inbox email identifier contains:

a locally interpreted string followed by the at-sign character (“@”)
followed by an Internet domain name in a dot-atom form. The domain portion identifies the mail exchanger name (MDA)

local-part@domain

Email server may support the addition of tag after the local-part where the local part and the tag are separated by a + or -

This tag then serves generally for routing or analytics purpose.

Example:

[email protected]

The email provider or SMTP server must support email tags. To check, just send an email to [email protected] is delivered to the email [email protected].

An address can be specified as:

the (envelope) sender- This is the address where delivery problems are sent to. (f option with sendmail)
the author (From: header)

As for URL, you can also rewrite an email address, meaning that the email will be delivered to the email server but at another email address.

Examples of address rewriting ¹⁾ :

username -> [email protected]
username@hostname -> [email protected]

sending: [email protected] -> [email protected]
receiving: [email protected] -> [email protected]

forwarding: Replace an internal address by an external address. Example: When sending mail from a home computer to the Internet.

[email protected] -> [email protected]

Mailing List: Replace an address by multiple addresses. For example, replace the address of an alias by the addresses listed under that alias.

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