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9b26804b58
Added more text to the "README-SGML" document on how to set up environment on FreeBSD. Still need to do NetBSD.
227 lines
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3.9 KiB
HTML
227 lines
No EOL
3.9 KiB
HTML
<HTML
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><HEAD
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><TITLE
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>The BIND 9 Lightweight Resolver</TITLE
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><META
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NAME="GENERATOR"
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CONTENT="Modular DocBook HTML Stylesheet Version 1.57"><LINK
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REL="HOME"
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HREF="Bv9ARM.html"><LINK
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REL="PREVIOUS"
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TITLE="Advanced Concepts"
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HREF="Bv9ARM.ch04.html"><LINK
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REL="NEXT"
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TITLE="BIND 9 Configuration Reference"
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HREF="Bv9ARM.ch06.html"></HEAD
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><BODY
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CLASS="chapter"
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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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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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></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="Bv9ARM.ch04.html"
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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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></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="Bv9ARM.ch06.html"
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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="chapter"
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><H1
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><A
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NAME="ch05"
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>Chapter 5. The <SPAN
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CLASS="acronym"
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>BIND</SPAN
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> 9 Lightweight Resolver</A
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></H1
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><DIV
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CLASS="TOC"
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><DL
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><DT
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><B
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>Table of Contents</B
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></DT
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><DT
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>5.1. <A
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HREF="Bv9ARM.ch05.html#AEN989"
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>The Lightweight Resolver Library</A
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></DT
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><DT
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>5.2. <A
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HREF="Bv9ARM.ch05.html#AEN995"
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>Running a Resolver Daemon</A
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></DT
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></DL
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></DIV
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><DIV
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CLASS="sect1"
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><H1
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CLASS="sect1"
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><A
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NAME="AEN989"
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>5.1. The Lightweight Resolver Library</A
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></H1
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><P
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>Traditionally applications have been linked with a stub resolver
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library that sends recursive DNS queries to a local caching name
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server.</P
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><P
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>IPv6 introduces new complexity into the resolution process,
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such as following A6 chains and DNAME records, and simultaneous
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lookup of IPv4 and IPv6 addresses. These are hard or impossible
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to implement in a traditional stub resolver.</P
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><P
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>Instead, <SPAN
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CLASS="acronym"
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>BIND</SPAN
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> 9 provides resolution services to local clients
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using a combination of a lightweight resolver library and a resolver
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daemon process running on the local host. These communicate using
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a simple UDP-based protocol, the "lightweight resolver protocol"
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that is distinct from and simpler than the full DNS protocol.</P
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></DIV
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><DIV
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CLASS="sect1"
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><H1
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CLASS="sect1"
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><A
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NAME="AEN995"
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>5.2. Running a Resolver Daemon</A
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></H1
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><P
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>To use the lightweight resolver interface, the system must
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run the resolver daemon <B
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CLASS="command"
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>lwresd</B
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>.</P
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><P
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>Applications using the lightweight resolver library will make
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UDP requests to the IPv4 loopback address (127.0.0.1) on port 921.
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The daemon will try to find the answer to the questions "what are the
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addresses for host <SPAN
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CLASS="systemitem"
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>foo.example.com</SPAN
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>?" and "what are
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the names for IPv4 address 204.152.184.79?"</P
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><P
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>The daemon currently only looks in the DNS, but in the future
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it may use other sources such as <TT
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CLASS="literal"
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>/etc/hosts</TT
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>,
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NIS, etc.</P
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><P
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>The <B
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CLASS="command"
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>lwresd</B
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> daemon is essentially a stripped-down,
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caching-only name server that answers requests using the lightweight
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resolver protocol rather than the DNS protocol. Because it needs
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to run on each host, it is designed to require no or minimal configuration.
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It uses the name servers listed on <B
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CLASS="command"
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>nameserver</B
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> lines
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in <TT
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CLASS="filename"
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>/etc/resolv.conf</TT
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> as forwarders, but is also
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capable of doing the resolution autonomously if none are specified.</P
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></DIV
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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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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="Bv9ARM.ch04.html"
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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="Bv9ARM.html"
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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="Bv9ARM.ch06.html"
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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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>Advanced Concepts</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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> </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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><SPAN
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CLASS="acronym"
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>BIND</SPAN
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> 9 Configuration Reference</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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> |