/etc/dhcpd.conf

ddns-updates off;

ddns-update-style interim;

authoritative;

shared-network local {

        subnet *.*.*.* netmask 255.255.255.0 {

                range *.*.*.* *.*.*.*;

                option routers *.*.*.*;

                option subnet-mask 255.255.255.0;

                option domain-name "XXXXX";

                option domain-name-servers *.*.*.*;

                deny unknown-clients;

                host trusted1 {

                        hardware ethernet *:*:*:*:*:*;

                        fixed-address *.*.*.*;

                }

}

        subnet 192.168.0.0 netmask 255.255.255.0 {

                range 192.168.0.2 192.168.0.10;

                option routers 192.168.0.1;

                option subnet-mask 255.255.255.0;

                option domain-name-servers 192.168.0.1;

                allow unknown-clients;

        }

}

IPtables is Fun!

Suddenly everything is kittens! It's kitten net.

/sbin/iptables -A PREROUTING -s 192.168.0.0/255.255.255.0 -p tcp -j DNAT --to-destination 64.111.96.38

For the uninitiated, this redirects all traffic to kittenwar.

For more fun, we set iptables to forward everything to a transparent squid proxy running on port 80 on the machine.

/sbin/iptables -A PREROUTING -s 192.168.0.0/255.255.255.0 -p tcp -m tcp --dport 80 -j DNAT --to-destination 192.168.0.1

That machine runs squid with a trivial redirector that downloads images, uses mogrify to turn them upside down and serves them out of it's local webserver.

The redirection script

#!/usr/bin/perl

$|=1;

$count = 0;

$pid = $$;

while (<>) {

        chomp $_;

        if ($_ =~ /(.*\.jpg)/i) {

                $url = $1;

                system("/usr/bin/wget", "-q", "-O","/space/WebPages/images/$pid-$count.jpg", "$url");

                system("/usr/bin/mogrify", "-flip","/space/WebPages/images/$pid-$count.jpg");

                print "http://127.0.0.1/images/$pid-$count.jpg\n";

        }

        elsif ($_ =~ /(.*\.gif)/i) {

                $url = $1;

                system("/usr/bin/wget", "-q", "-O","/space/WebPages/images/$pid-$count.gif", "$url");

                system("/usr/bin/mogrify", "-flip","/space/WebPages/images/$pid-$count.gif");

                print "http://127.0.0.1/images/$pid-$count.gif\n";

        }

        else {

                print "$_\n";;

        }

        $count++;

}

Then the internet looks like this!

And if you replace flip with -blur 4 you get the blurry-net