This time, however, you ran sendmail
directly and supplied only a body; the header was added by sendmail.
1.5.2 The Header
Let??™s examine the header in more detail:
From you@Here.US.EDU Fri Dec 14 08:11:44 2007
Received: (from you@localhost)
by Here.US.EDU (8.12.7/8.12.7)
id d8BILug12835 for you; Fri, 14 Dec 2007 08:11:44 -0600 (MDT)
Date: Fri, 14 Dec 2007 08:11:43
From: you@Here.US.EDU (Your Full Name)
Message-Id: 200712141511.d872mLW24467@Here.US.EDU>
To: you ?†? might be something else (see ?§24.9.81 on page 1060)
Notice that most header lines start with a word followed by a colon. Each word tells
what kind of information the rest of the line contains. Many types of header lines can
appear in a mail message. Some are mandatory, some are optional, and some can
appear many times. Those that appeared in the message you mailed to yourself were
all mandatory.* That??™s why sendmail added them to your message. The line starting
with the five characters ???From ??? (the fifth character is a space) is added by some programs
(such as /bin/mail) but not by others (such as mh).
Figure 1-1. Every mail message is composed of a header and a body
* We are fudging for simplicity. The Message-ID: header is not strictly mandatory.
From you@Here.US.EDU Fri Dec 14 08:11:44 2007
To: you
This is a one-line message.
The Header
The Body
Blank Line
This is the Title of the Book, eMatter Edition
Copyright ?© 2007 O??™Reilly & Associates, Inc.
Pages:
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50