223 lines
3.9 KiB
HTML
223 lines
3.9 KiB
HTML
<HTML
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>More About Network Address Translation</TITLE
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TITLE="IP Masquerade and Network Address Translation"
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TITLE="Handling Name Server Lookups"
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>Linux Network Administrators Guide</TH
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><TD
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>Chapter 11. IP Masquerade and Network Address Translation</TD
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WIDTH="10%"
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><H1
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><A
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NAME="AEN9803"
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>11.5. More About Network Address Translation</A
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></H1
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><P
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> The <I
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CLASS="EMPHASIS"
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>netfilter</I
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> software is capable of many different types
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of Network Address Translation. IP Masquerade is one simple application of it.</P
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><P
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>It is possible, for example, to build NAT rules that translate only certain
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addresses or ranges of addresses and leave all others untouched, or to
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translate addresses into pools of addresses rather than just a single address,
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as masquerade does. You can in fact use the <B
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CLASS="COMMAND"
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>iptables</B
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> command
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to generate NAT rules that map just about anything, with
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combinations of matches using any of the standard attributes, such as source
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address, destination address, protocol type, port number, etc.</P
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><P
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> Translating the Source Address of a datagram is referred to as “Source
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NAT,” or <TT
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CLASS="LITERAL"
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>SNAT</TT
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>, in the <I
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CLASS="EMPHASIS"
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>netfilter</I
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>
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documentation. Translating the Destination Address of a datagram is known as
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“Destination NAT,” or <TT
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CLASS="LITERAL"
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>DNAT</TT
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>. Translating the TCP
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or UDP port is known by the term <TT
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CLASS="LITERAL"
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>REDIRECT</TT
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>.
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<TT
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CLASS="LITERAL"
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>SNAT</TT
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>, <TT
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CLASS="LITERAL"
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>DNAT</TT
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>, and
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<TT
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CLASS="LITERAL"
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>REDIRECT</TT
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> are targets that you may use with the
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<B
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CLASS="COMMAND"
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>iptables</B
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> command to build more complex and sophisticated
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rules.</P
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><P
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>
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The topic of Network Address Translation and its uses warrants at least a
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whole chapter of its own.<A
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NAME="AEN9827"
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HREF="#FTN.AEN9827"
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>[1]</A
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> Unfortunately we don't have the space in this book to cover it in
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any greater depth. You should read the IPTABLES-HOWTO for more information, if
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you're interested in discovering more about how you might use Network Address
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Translation.</P
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></DIV
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><H3
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CLASS="FOOTNOTES"
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>Notes</H3
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><TABLE
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HREF="x9803.html#AEN9827"
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>[1]</A
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></TD
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><TD
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ALIGN="LEFT"
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VALIGN="TOP"
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WIDTH="95%"
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><P
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>... and perhaps even a whole book!</P
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></TD
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HREF="x-087-2-masq.namelookups.html"
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>Prev</A
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>Handling Name Server Lookups</TD
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WIDTH="34%"
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>ImportantNetwork Features</TD
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