What is a Mail User Agent?
A mail user agent (MUA) is an email program; software designed to collect and send electronic mail. It is also referred to as an email program, or email client. The term “mail user agent” is less familiar to the average person, but is used in email headers. The headers of the email supply information to the mail servers or computers that handle transferring messages across networks like the Internet. Networking standards have been established to make exchange of messages possible from a virtual unlimited pool of clients. To this end every mail user agent handles text messages, graphics and attached messages in a similar manner. When a user sends an email an array of information is sent with the message to ensure it reaches its destination. This extra “addressing” information is included in the headers, along with the name of the email program as the “mail user agent.” Email sent from an Internet Service Provider (ISP) is handled by that ISPs mail server, which is the equivalent of an e
