\documentclass[a4j]{jarticle}
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\usepackage{graphicx}
\begin{document}
\begin{center}
 \Large{NAT ( Network Address Translation )}
\end{center}
\begin{flushright}
 \today\\
 $BJw(B $BH%;K(B
\end{flushright}
\section{NAT$B$H$O(B}
$B%W%i%$%Y!<%H%"%I%l%9$7$+;}$?$J$$$h$&$JFbIt%M%C%H>e$N%[%9%H$G$O!$(B
$BDL>o$O%0%m!<%P%k%"%I%l%9$r;}$D30It$N%^%7%s$H$ODL?.$G$-$J$$!%%W%i(B
$B%$%Y!<%H%"%I%l%9$OFbIt%M%C%H$@$1$GM-8z$G!$30It%M%C%H$G$O!$%W%i%$%Y!<%H%"(B
$B%I%l%9$O0UL#$r;}$?$J$$$?$a$G$"$k!%$D$^$j30It$N%^%7%s$HDL?.$9$k$K$O!$%0%m!<%P%k(B
$B%"%I%l%9$,I,MW$H$J$k!$$=$3$G!$$9$Y$F$N%^%7%s$K%0%m!<%P%k%"%I%l%9$r3d$jEv(B
$B$F$k$H$3$NLdBj$O2r7h$G$-$k$,!$$3$N2r7hK!$O!$(BIP$B%"%I%l%9$N8O3i!$%;%-%e%j%F%#(B
$B>e$NK>$^$7$/$J$$(B($B30It$+$iIT@5%"%/%;%9$r<u$1$k4m81@-$,$9$Y$F$N%^%7%s$KH/(B
$B@8$9$k(B)$B$H8@$&E@$G8=<BE*$J2r7hK!$G$O$J$$!%$=$3$G%W%i%$%Y!<%H%"%I(B
$B%l%9$r;}$DFbIt%^%7%s$+$i$G$b!$%0%m!<%P%k%"%I%l%9$r;}$D30It%^%7%s$HDL?.$G(B
$B$-$k$h$&$K(BIP$B%"%I%l%9$NIU$1JQ$($r9T$&5;=Q$,(BNAT ( Network Address
Translation )$B$G$"$k!%(B

$BNc$r>e$2$k$H!$(BNAT$B%5!<%P!<$O!$FbIt%M%C%H$N%^%7%s(B(eric.4f.db.is.kyuhsu-u.ac.jp :
192.168.33.57)$B$,30It$K$"$k%^%7%s(B(minako.db.is.kyuhsu-u.ac.jp :
133.5.18.160 )$B$KDL?.$7$h$&$H$9$k$H(Beric$B$+$iAw?.85%"%I%l%9$,(B
192.168.33.57$B$GAw?.@h%"%I%l%9$,(B 133.5.18.160 $B$G$"$k%Q%1%C%H$,$^$:Aw?.$5(B
$B$l$k!%$3$N%Q%1%C%H$O(BDefaultrouter$B$G$"$k(B
yumi/ami(192.168.33.1/133.5.18.197)(NAT$B%5!<%P!<(B)$B$KAw$i$l!$$3$3$G(BIP$B$NIU$1(B
$BBe$($,9T$o$l$k!%(Byumi$B$,(Beric$B$+$i<u$1<h$C$?%Q%1%C%H$NAw?.85%"%I%l%9$r(B
133.5.18.197$B$KJQ99$7$F!$(Bami$B$+$iAw?.$5$l$?%Q%1%C%H$H$7$F(Bminako$B$KAw?.(B
$B$9$k!%$3$N$H$-(Bami$B$O$3$NJQ49$r$"$k0lDj4|4V3P$($F$*$-!$(Bminako$B$+$i%Q%1%C%H(B
$B$,La$C$F$/$k$H!$$=$l$,@h$[$I(BNAT$B$G%"%I%l%9JQ49$7$?$b$N$G$"$k$H3NG'$5$l$k(B
$B$H$=$N%Q%1%C%H$NAw?.@h%"%I%l%9$r(B 192.168.33.57 $B$KJQ99$7(B eric $B$KAw?.$9$k!%(B
$B$3$N$h$&$J(BNAT$B%5!<%P!<$NF0:n$K$h$jFbIt%M%C%H$+$i30It$XDL?.$,2DG=$H$J$k!%(B

\begin{figure}[htbp]
 \begin{center}
  \includegraphics{nat.eps}
  \caption{NAT$B$G$NJQ49Nc(B}
 \end{center}
\end{figure}

\section{$B8&5f<<$N(BNAT$B%5!<%P!<(B}
$B8&5f<<$G$O!$(BNAT$B%5!<%P$O(B4$B3,$G$O(B yumi/ami $B!$(B3$B3,$G$O(B yoda/luke $B$,9T$C$F$$$k!%(B
\section{NAT$B%5!<%P!<$N@_Dj(B}
\begin{enumerate}
 \item $B0J2<$N(BOption$B$r$D$1$F%+!<%M%k$r:F%3%s%Q%$%k$9$k!%(B\\
       options IPFIREWALL\\
       options IPDIVERT
 \item /etc/rc.conf $B$K0J2<$N0l9T$r2C$($k!%(B\\
       gateway\_enable="YES"
 \item natd$B$rN)$A>e$2$k!%(B\\
       \% natd -interface tx0\\
       $B$3$3$G!$(Btx0$B$O30ItMQ$N%M%C%H%o!<%/%+!<%I$G$"$k!%(B/etc/rc.conf $B$K0J(B
       $B2<$N9T$r2C$($F$*$/$H5/F0;~$K!$(Bnatd$B$r5/F0$7$F$/$l$k!%(B
       natd\_enable="YES"\\
       natd\_interface="tx0"
 \item /etc/rc.firewall$B$r0J2<$N%3%^%s%I$,<B9T$5$l$k$h$&$K=q$-49$($k!%(B\\
       /sbin/ipfw -f flush\\
       /sbin/ipfw add divert natd all from any to any via tx0\\
       /sbin/ipfw add pass all from any to any\\
 \item /etc/rc.conf$B$K(B $B0J2<$N#19T$rDI2C!%(B\\
       firewall\_enable=YES\\
       $B$3$N9T$rDI2C$9$k$3$H$K$h$j!$5/F0;~$K(B/etc/firewall$B$K=q$$$F$"$k%9%/(B
       $B%j%W%H$,<B9T$5$l$k!%(B
\end{enumerate}
\section{$B<B=,(B}
NAT$B%5!<%P!<$O!$(BLAN$B$r9=C[$9$kI,MW$b$"$k$7!$%M%C%H%o!<%/%+!<%I$b#2KgI,MW$J(B
$B$N$G!$<B=,$G(BNAT$B%5!<%P$r9=C[$9$k$N$OBgJQ$G$9!%$=$3$G:#2s$O!$30It%M%C%H%o!<(B
$B%/$K@\B3$9$k$H$-$K$O!$(BNAT$B%5!<%P!<$rDL$7$F@\B3$7$F$$$k$3$H$r3N$+$a$F$/$@(B
$B$5$$!%0J2<$N%3%^%s%I$r<B9T$7$^$9!%(B\\
\% traceroute minako\\
$B0lEY!$(Byumi$B$r7PM3$7$F(Bminako$B$K$D$J$,$C$F$$$k$N$,$o$+$k$H;W$$$^$9!%(B
\end{document}