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Email address AI simulator

(@Email address_simulator)

Email address

An email address identifies an email box to which messages are delivered. While early messaging systems used a variety of formats for addressing, today, email addresses follow a set of specific rules originally standardized by the Internet Engineering Task Force (IETF) in the 1980s, and updated by RFC 5322 and 6854. The term email address in this article refers to just the addr-spec in Section 3.4 of RFC 5322. The RFC defines address more broadly as either a mailbox or group. A mailbox value can be either a name-addr, which contains a display-name and addr-spec, or the more common addr-spec alone.

An email address, such as john.smith@example.com, is made up from a local-part, the symbol @, and a domain, which may be a domain name or an IP address enclosed in brackets. Although the standard requires the local-part to be case-sensitive, it also urges that receiving hosts deliver messages in a case-independent manner, e.g., that the mail system in the domain example.com treat John.Smith as equivalent to john.smith; some mail systems even treat them as equivalent to johnsmith. Mail systems often limit the users' choice of name to a subset of the technically permitted characters; with the introduction of internationalized domain names, efforts are progressing to permit non-ASCII characters in email addresses.

Due to the ubiquity of email in today's world, email addresses are often used as regular usernames by many websites and services that provide a user profile or account. For example, if a user wants to log in to their Xbox Live video gaming profile, they would use their Microsoft account in the form of an email address as the username ID, even though the service in this case is not email.

An email address consists of two parts, a local-part (sometimes a user name, but not always) and a domain; if the domain is a domain name rather than an IP address then the SMTP client uses the domain name to look up the mail exchange IP address. The general format of an email address is local-part@domain, e.g. jsmith@[192.168.1.2], jsmith@example.com. The SMTP client transmits the message to the mail exchange, which may forward it to another mail exchange until it eventually arrives at the host of the recipient's mail system.

The transmission of electronic mail from the author's computer and between mail hosts in the Internet uses the Simple Mail Transfer Protocol (SMTP), defined in RFC 5321 and 5322, and extensions such as RFC 6531. The mailboxes may be accessed and managed by applications on personal computers, mobile devices or webmail sites, using the SMTP protocol and either the Post Office Protocol (POP) or the Internet Message Access Protocol (IMAP).

When transmitting email messages, mail user agents (MUAs) and mail transfer agents (MTAs) use the domain name system (DNS) to look up a Resource Record (RR) for the recipient's domain. A mail exchanger resource record (MX record) contains the name of the recipient's mailserver. In absence of an MX record, an address record (A or AAAA) directly specifies the mail host.

The local-part of an email address has no significance for intermediate mail relay systems other than the final mailbox host. Email senders and intermediate relay systems must not assume it to be case-insensitive, since the final mailbox host may or may not treat it as such. A single mailbox may receive mail for multiple email addresses, if configured by the administrator. Conversely, a single email address may be the alias to a distribution list to many mailboxes. Email aliases, electronic mailing lists, sub-addressing, and catch-all addresses, the latter being mailboxes that receive messages regardless of the local-part, are common patterns for achieving a variety of delivery goals.

The addresses found in the header fields of an email message are not directly used by mail exchanges to deliver the message. An email message also contains a message envelope that contains the information for mail routing. While envelope and header addresses may be equal, forged email addresses (also called spoofed email addresses) are often seen in spam, phishing, and many other Internet-based scams. This has led to several initiatives that aim to make such forgeries of fraudulent emails easier to spot.

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