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Fully qualified domain address
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<p>A fully qualified domain address (FQDA) is a <a href="/facts/String_(computer_science)/4ChJu5WS">string</a> forming an <a href="/facts/Internet/Xw1rVvJU">Internet</a> <a href="/facts/E-mail/6pD9GLtI">e-mail</a> address. It was defined by the <a href="/facts/Internet_Engineering_Task_Force/tIcCsFhX">Internet Engineering Task Force</a> in RFC 3801 for the use in voice profiles for Internet mail, but has been used on the Internet as early as 1988. </p><p>A FQDA is composed of a <i>local part</i>, followed by the symbol @ and the <a href="/facts/Fully_qualified_domain_name/UgFMPQWD">fully qualified domain name</a> (FQDN) of the host responsible for a mailbox. </p><p>An example of a FQDA is: localpart@mailhost.example.com. The local part usually denotes a username, while the fully qualified domain name is used by <a href="/facts/Mail_transfer_agent/9SJG5sbb">mail transfer agents</a> to determine the <a href="/facts/IP_address/z9V22Sw9">IP address</a> of the host by querying the <a href="/facts/Domain_Name_System/rfxdWFsj">Domain Name System</a>. </p>