65 lines
3.0 KiB
HTML
65 lines
3.0 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>Message Routing and Delivery</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="node208.html">Routing Messages</A>
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<B>Up:</B> <A HREF="node198.html">Getting smail Up and </A>
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<B> Previous:</B> <A HREF="node206.html">Miscellaneous config Options</A>
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<BR> <P>
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<H1><A NAME="SECTION0016600000">Message Routing and Delivery</A></H1>
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<P>
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<A NAME="smaildelivery"></A>
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<A NAME="7811"></A>
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<P>
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smail splits up mail delivery into three different tasks,
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the router, director, and transport module.
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<P>
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The router module resolves all remote addresses, determining to which
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host the message should be sent to next, and which transport must be
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used. Depending on the nature of the link, different transports
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such as UUCP or SMTP may be used.
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<P>
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Local addresses are given to the director task which resolves any
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forwarding or aliasing. For example, the address might be an alias or a
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mailing list, or the user might want to forward her mail to another
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address. If the resulting address is remote, it is handed to the router
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module for additional routing, otherwise it is assigned a transport for
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local delivery. By far the most common case will be delivery to a
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mailbox, but messages may also be piped into a command, or appended to
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some arbitrary file.
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<P>
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The transport module, finally, is responsible for whatever method
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of delivery has been chosen. It tries to deliver the message, and in
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case of failure either generates a bounce message, or defers it for
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a later retry.
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<P>
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<A NAME="7812"></A>
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<A NAME="7813"></A>
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<A NAME="7814"></A>
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With smail, you have much freedom in configuring these tasks.
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For each of them, a number of drivers are available, from
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which you can choose those you need. You describe them to smail
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in a couple of files, namely routers, directors, and
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transports, located in /usr/lib/smail. If these files do not exist,
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reasonable defaults are assumed that should be suitable for many sites
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that either use SMTP or UUCP for transport. If you want to change
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smail's routing policy, or modify a transport, you should get the
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sample files from the smail source distribution,<A HREF="footnode.html#7815"><IMG ALIGN=BOTTOM ALT="gif" SRC="foot_motif.gif"></A> copy the sample files to /usr/lib/smail, and modify them according to your
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needs. Sample configuration files are also given in
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Appendix-<A HREF="node285.html#appendixsmail"><IMG ALIGN=BOTTOM ALT="gif" SRC="cross_ref_motif.gif"></A>.
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<P>
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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="node208.html">Routing Messages</A>
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<B>Up:</B> <A HREF="node198.html">Getting smail Up and </A>
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<B> Previous:</B> <A HREF="node206.html">Miscellaneous config Options</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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</BODY>
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</HTML>
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