254 lines
4.3 KiB
HTML
254 lines
4.3 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<HTML
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><HEAD
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><TITLE
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>Options and Settings</TITLE
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><META
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NAME="GENERATOR"
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CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK
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REL="HOME"
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TITLE="Spam Filtering for Mail Exchangers"
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HREF="index.html"><LINK
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REL="UP"
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TITLE="Exim Implementation"
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HREF="exim.html"><LINK
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REL="PREVIOUS"
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TITLE="The Exim Configuration File"
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HREF="exim-configfile.html"><LINK
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REL="NEXT"
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TITLE="Building the ACLs - First Pass"
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HREF="exim-firstpass.html"></HEAD
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><BODY
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CLASS="section"
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BGCOLOR="#FFFFFF"
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TEXT="#000000"
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LINK="#0000FF"
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VLINK="#840084"
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ALINK="#0000FF"
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><DIV
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CLASS="NAVHEADER"
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><TABLE
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SUMMARY="Header navigation table"
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WIDTH="100%"
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BORDER="0"
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CELLPADDING="0"
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CELLSPACING="0"
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><TR
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><TH
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COLSPAN="3"
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ALIGN="center"
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>Spam Filtering for Mail Exchangers: </TH
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></TR
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><TR
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><TD
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WIDTH="10%"
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ALIGN="left"
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VALIGN="bottom"
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><A
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HREF="exim-configfile.html"
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ACCESSKEY="P"
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>Prev</A
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></TD
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><TD
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WIDTH="80%"
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ALIGN="center"
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VALIGN="bottom"
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>Appendix A. Exim Implementation</TD
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><TD
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WIDTH="10%"
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ALIGN="right"
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VALIGN="bottom"
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><A
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HREF="exim-firstpass.html"
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ACCESSKEY="N"
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>Next</A
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></TD
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></TR
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></TABLE
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><HR
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ALIGN="LEFT"
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WIDTH="100%"></DIV
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><DIV
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CLASS="section"
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><H1
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CLASS="section"
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><A
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NAME="exim-options"
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></A
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>A.3. Options and Settings</H1
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><P
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> The main section of the Exim configuration file (before the
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first <TT
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CLASS="option"
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>begin</TT
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> keyword) contains various macros,
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policy controls, and other general settings. Let us start by
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defining a couple of macros we will use later:
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<TABLE
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BORDER="0"
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BGCOLOR="#E0E0E0"
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WIDTH="100%"
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><TR
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><TD
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><FONT
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COLOR="#000000"
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><PRE
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CLASS="screen"
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> # Define the message size limit; we will use this in the DATA ACL.
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MESSAGE_SIZE_LIMIT = 10M
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# Maximum message size for which we will run Spam or Virus scanning.
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# This is to reduce the load imposed on the server by very large messages.
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MESSAGE_SIZE_SPAM_MAX = 1M
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# Macro defining a secret that we will use to generate various hashes.
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# PLEASE CHANGE THIS!.
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SECRET = <TT
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CLASS="parameter"
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><I
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>some-secret</I
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></TT
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>
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</PRE
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></FONT
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></TD
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></TR
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></TABLE
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>
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</P
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><P
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> Let us tweak some general Exim settings:
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<TABLE
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BORDER="0"
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BGCOLOR="#E0E0E0"
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WIDTH="100%"
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><TR
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><TD
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><FONT
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COLOR="#000000"
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><PRE
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CLASS="screen"
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> # Treat DNS failures (SERVFAIL) as lookup failures.
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# This is so that we can later reject sender addresses
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# within non-existing domains, or domains for which no
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# nameserver exists.
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dns_again_means_nonexist = !+local_domains : !+relay_to_domains
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# Enable HELO verification in ACLs for all hosts
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helo_try_verify_hosts = *
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# Remove any limitation on the maximum number of incoming
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# connections we can serve at one time. This is so that while
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# we later impose SMTP transaction delays for spammers, we
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# will not refuse to serve new connections.
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smtp_accept_max = 0
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# ..unless the system load is above 10
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smtp_load_reserve = 10
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# Do not advertise ESMTP "PIPELINING" to any hosts.
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# This is to trip up ratware, which often tries to pipeline
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# commands anyway.
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pipelining_advertise_hosts = :
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</PRE
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></FONT
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></TD
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></TR
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></TABLE
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>
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</P
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><P
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> Finally, we will point some Exim policy controls to five ACLs
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that we will create to evaluate the various stages of an
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incoming SMTP transaction:
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<TABLE
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BORDER="0"
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BGCOLOR="#E0E0E0"
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WIDTH="100%"
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><TR
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><TD
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><FONT
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COLOR="#000000"
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><PRE
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CLASS="screen"
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> acl_smtp_connect = acl_connect
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acl_smtp_helo = acl_helo
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acl_smtp_mail = acl_mail_from
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acl_smtp_rcpt = acl_rcpt_to
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acl_smtp_data = acl_data
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</PRE
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></FONT
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></TD
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></TR
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></TABLE
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>
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</P
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></DIV
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><DIV
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CLASS="NAVFOOTER"
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><HR
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ALIGN="LEFT"
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WIDTH="100%"><TABLE
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SUMMARY="Footer navigation table"
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WIDTH="100%"
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BORDER="0"
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CELLPADDING="0"
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CELLSPACING="0"
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><TR
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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><A
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HREF="exim-configfile.html"
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ACCESSKEY="P"
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>Prev</A
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></TD
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><TD
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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><A
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HREF="index.html"
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ACCESSKEY="H"
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>Home</A
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></TD
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><TD
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WIDTH="33%"
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ALIGN="right"
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VALIGN="top"
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><A
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HREF="exim-firstpass.html"
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ACCESSKEY="N"
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>Next</A
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></TD
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></TR
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><TR
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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>The Exim Configuration File</TD
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><TD
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WIDTH="34%"
|
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ALIGN="center"
|
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VALIGN="top"
|
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><A
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HREF="exim.html"
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ACCESSKEY="U"
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>Up</A
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></TD
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><TD
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WIDTH="33%"
|
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ALIGN="right"
|
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VALIGN="top"
|
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>Building the ACLs - First Pass</TD
|
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></TR
|
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></TABLE
|
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></DIV
|
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></BODY
|
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></HTML
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> |