The header of an e-mail is the part of an e-mail message that contains the “who, what, where” information. The most common headers are the “To:”, “From:” and “Subject” lines. Carbon Copy, “CC:” is another one you might see often. There are many other headers you could see in a message but you may not have access to edit them.
These headers contain information about the mail program used to create the message, what mail server sent the message, what mail server received the message, a message id that is used by the sending server, etc.
By default, most e-mail programs only display a few headers, “To:”, “From:”, “Subject:”, maybe “CC:”, and maybe “BCC:”. With the volume of SPAM mail, unsolicited e-mail, the additional headers can be used to determine where the SPAM came from, since most of the time the “From:” field contains a fake address.
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