110 lines
5.6 KiB
HTML
110 lines
5.6 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
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<!--Converted with LaTeX2HTML 96.1-c (Feb 29, 1996) by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds -->
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<HTML>
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<HEAD>
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<TITLE>Electronic Mail</TITLE>
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</HEAD>
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<BODY LANG="EN">
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<A HREF="node1.html"><IMG WIDTH=65 HEIGHT=24 ALIGN=BOTTOM ALT="contents" SRC="contents_motif.gif"></A> <BR>
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<B> Next:</B> <A HREF="node187.html">What is a Mail </A>
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<B>Up:</B> <A HREF="nag.html">The Network Administrators' Guide</A>
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<B> Previous:</B> <A HREF="node185.html">Log Files</A>
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<BR> <P>
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<H1><A NAME="SECTION0015000000">Electronic Mail</A></H1>
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<A NAME="mail"></A>
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One of the most prominent uses of networking since the first networks
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were devised, has been electronic mail. It started as a simple service
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that copied a file from one machine to another, and appended it to the
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recipient's <em>mailbox</em> file. Basically, this is still what email is
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all about, although an ever growing net with its complex routing
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requirements and its ever increasing load of messages has made a more
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elaborate scheme necessary.
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<P>
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Various standards of mail exchange have been devised. Sites on the
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Internet adhere to one laid out in RFC-822, augmented by some RFCs that
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describe a machine-independent way of transferring special characters,
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and the like. Much thought has also been given recently to ``multi-media
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mail'', which deals with including pictures and sound in mail messages.
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Another standard, X.400, has been defined by CCITT.
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<P>
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Quite a number of mail transport programs have been implemented for
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systems. One of the best-known is the University of Berkeley's
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sendmail, which is used on a number of platforms. The original
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author was Eric Allman, who is now actively working on the
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sendmail team again. There are two ports of
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sendmail-5.56c available, one of which will be described in
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chapter-<A HREF="node218.html#sendmail"><IMG ALIGN=BOTTOM ALT="gif" SRC="cross_ref_motif.gif"></A>. The sendmail version currently being
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developed is 8.6.5.
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<P>
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The mail agent most commonly used with is smail-3.1.28,
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written and copyrighted by Curt Landon Noll and Ronald S.-Karr. This is the
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one included in most distributions. In the following, we will
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refer to it simply as smail, although there are other versions of it
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which are entirely different, and which we don't describe here.
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<P>
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Compared to sendmail, smail is rather young. When handling
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mail for a small site without complicated routing requirements, their
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capabilities are pretty close. For large sites, however, sendmail
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always wins, because its configuration scheme is much more flexible.
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<P>
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Both smail and sendmail support a set of configuration
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files that have to be customized. Apart from the information that is
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required to make the mail subsystem run (such as the local hostname),
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there are many more parameters that may be tuned. sendmail's
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main configuration file is very hard to understand at first. It looks as
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if your cat had taken a nap on your keyboard with the shift key pressed.
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smail configuration files are more structured and easier to
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understand than sendmail's, but don't give the user as much power
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in tuning the mailer's behavior. However, for small UUCP or Internet
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sites the work required in setting up any of them is roughly the same.
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<P>
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In this chapter, we will deal with what email is and what issues you as
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an administrator will have to deal with. Chapters-<A HREF="node198.html#smail"><IMG ALIGN=BOTTOM ALT="gif" SRC="cross_ref_motif.gif"></A>
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and-<A HREF="node218.html#sendmail"><IMG ALIGN=BOTTOM ALT="gif" SRC="cross_ref_motif.gif"></A> will give instructions on setting up smail and
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sendmail for the first time. The information provided there
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should suffice to get smaller sites operational, but there are many more
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options, and you can spend many happy hours in front of your computer
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configuring the fanciest features.
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<P>
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Toward the end of the current chapter we will briefly cover setting up
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elm, a very common mail user agent on many ish systems,
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including .
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<P>
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For more information about issues specific to electronic mail on
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, please refer to the Electronic Mail HOWTO by Vince Skahan,
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which is posted to comp.os.linux.announce regularly. The
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source distributions of elm, smail and sendmail
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also contain very extensive documentation that should answer most of
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your questions on setting them up. If you are looking for information
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on email in general, there's a number of RFCs that deal with this
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topic. They are listed in the bibliography at the end of the book.
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<P>
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<BR> <HR>
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<UL>
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<LI> <A HREF="node187.html#SECTION0015100000">What is a Mail Message?</A>
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<LI> <A HREF="node188.html#SECTION0015200000">How is Mail Delivered?</A>
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<LI> <A HREF="node189.html#SECTION0015300000">Email Addresses</A>
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<LI> <A HREF="node190.html#SECTION0015400000">How does Mail Routing Work?</A>
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<UL>
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<LI> <A HREF="node191.html#SECTION0015410000">Mail Routing on the Internet</A>
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<LI> <A HREF="node192.html#SECTION0015420000">Mail Routing in the UUCP World</A>
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<LI> <A HREF="node193.html#SECTION0015430000">Mixing UUCP and RFC-822</A>
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</UL>
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<LI> <A HREF="node194.html#SECTION0015500000">Pathalias and Map File Format</A>
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<LI> <A HREF="node195.html#SECTION0015600000">Configuring elm</A>
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<UL>
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<LI> <A HREF="node196.html#SECTION0015610000">Global elm Options</A>
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<LI> <A HREF="node197.html#SECTION0015620000">National Character Sets</A>
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</UL>
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</UL>
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<HR><A HREF="node1.html"><IMG WIDTH=65 HEIGHT=24 ALIGN=BOTTOM ALT="contents" SRC="contents_motif.gif"></A> <BR>
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<B> Next:</B> <A HREF="node187.html">What is a Mail </A>
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<B>Up:</B> <A HREF="nag.html">The Network Administrators' Guide</A>
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<B> Previous:</B> <A HREF="node185.html">Log Files</A>
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<P><ADDRESS>
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<I>Andrew Anderson <BR>
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Thu Mar 7 23:22:06 EST 1996</I>
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</ADDRESS>
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</HTML>
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