m} to make a new mail buffer, and work with each mail buffer
independently.
+ Before using Emacs to send mail, you may need to customize the
+variable @code{send-mail-function} if your system is not set up to
+deliver mail directly via SMTP (@pxref{Mail Sending}). In addition,
+you may need to customize @code{user-mail-address} if the system
+cannot receive mail via SMTP (@pxref{Mail Headers}).
+
@menu
* Format: Mail Format. Format of a mail message.
* Headers: Mail Headers. Details of some standard mail header fields.
@cindex Mailclient
@vindex send-mail-function
The variable @code{send-mail-function} controls how the default mail
-user agent sends mail. It should be set to a function. In most
-cases, the default is @code{sendmail-send-it}, which delivers mail
-using @command{sendmail} (or a @command{sendmail}-compatible program).
-On Mac OS X and MS-Windows, however, the default is normally
-@code{mailclient-send-it}, which passes the mail buffer on to the
-system's designated mail client (see @file{mailclient.el}). To send
-mail through an SMTP server, set @code{send-mail-function} to
-@code{smtpmail-send-it} and set up the Emacs SMTP library
-(@pxref{Top,,Emacs SMTP Library, smtpmail, Sending mail via SMTP}).
-Another option is @code{feedmail-send-it} (see the commentary section
-of the @file{feedmail.el} package).
+user agent sends mail. Its value should be a function, which can be
+one of the following:
+
+@table @code
+@item sendmail-send-it
+Send mail using the system's default @command{sendmail} (or
+@command{sendmail}-compatible) program. This is the default on Unix
+and GNU, and works provided the system is a valid @dfn{mail host}
+(that is, provided it can deliver mail via SMTP).
+
+@item mailclient-send-it
+Pass the mail buffer on to the system's designated mail client (see
+@file{mailclient.el}). This is the default on Mac OS X and
+MS-Windows.
+
+@item smtpmail-send-it
+Send mail through an external mail host (e.g., your Internet service
+provider's SMTP server). You will need to tell Emacs how to contact
+the SMTP server, by customizing the variables
+@code{smtpmail-smtp-server} and @code{smtpmail-auth-credentials}.
+@xref{Top,,Emacs SMTP Library, smtpmail, Sending mail via SMTP}.
+
+@item feedmail-send-it
+This is similar to @code{sendmail-send-it}, but allows you to queue
+messages for later sending. See the commentary section in the file
+@file{feedmail.el} for more information.
+@end table
@node Header Editing
@subsection Mail Header Editing