Your Internet Consultant - The FAQs of Life Online

4.3. What goes in an e-mail header?

Every e-mail message has two parts: the header and the body. The message header is a lot like the front of an envelope. It contains the information needed to deliver the message, such as who it is to, who it is from. The header also contains a subject line. The message body, as you might expect, contains the actual text of your message. You don't need to worry much about your e-mail's headers, but they do prove useful. When you send e-mail, your mail program will prompt you for the recipient's name, a message subject, and other vital information and will automatically format the headers for you. In some circumstances, (a couple of them are mentioned in the following questions) you may want to manually edit your message headers.

Here is a list of the basic Internet mail headers and what they do:

From: Arlo T. Kitty <>

The From: line shows who a message is from. It always includes an e-mail address and sometimes includes the sender's "real" name, too. Luckily, my cats don't really send me e-mail.

Note: There are two basic formats for the From: line. One is in the form From: Arlo T. Kitty <> as shown above. The other is From: (Arlo T. Kitty).


The To: line contains the address of the primary recipient (or recipients) of the message. I say primary because other folks can get copies, too, as specified in the Cc: and Bcc: header lines. A To: line can contain as many addresses as you care to include. The addresses can be those of individuals, mailing lists, or programs that accept e-mail.

Message-Id: <>

Message-Id is a unique numeric identifier for the message. I have never found it useful, but it's always there.

Subject: We're low on cat chow!

The subject line is basic enough; it contains the sender's idea of the message's topic.

Date: Sun, 20 Feb 1994 11:11:36 PST

The Date: line tells you when the message was actually sent. Date lines can be mildly confusing--some of them tell you the send time at the originating computer site, and others convert the time to Greenwich Mean Time (GMT)--the time in Greenwich, England. I can never remember if California is seven or eight hours behind GMT because the time difference changes when daylight savings starts in late April.

Note: GMT is "ground zero" from the International Date Line, which is exactly 12 timezones away in either direction from Greenwich. Modern conventions have renamed GMT as Universal Time Coordinated (UTC) so you may see that notation, too.

Organization: Fuzzy Kitties R Us

The Organization: line is optional and may tell you who the senders work for or where they go to school, or it may contain a tiny advertisement for their service providers. Lots of people who choose to deny affiliation with any organizations use the field for silly messages and bogus firm names.


Cc stands for Carbon Copy and Bcc stands for Blind Carbon Copy. These fields help electronic mail mimic what you can do with traditional mail. Specifically, fire off copies to multiple people, either while announcing it or surreptitiously. Remember, the recipient never sees the Bcc: line. See the following questions for more on carbon copying.

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