This script parses the apache logfile from STDIN.

parse-apache-log.pl

#!/usr/bin/perl

# 
# by Keiya Chinen

use strict;
use warnings;

my %hosts;
while (my $line = <STDIN>) {
        $line =~ m/^.+?:80 ([\d\.]+)/;
        $hosts{$1}{'cnt'}++;
}

foreach my $k (keys %hosts) {
        my $host = gethostbyaddr(pack("C4", split(/\./, $k)), 2);
        $host = $k if not defined $host;
        if ($host =~ m/\.ne(?:t|\.\w+?)$/) {
                print "Provider\t$host ($k)\n";
        }
        elsif ($host =~ m/\.go(?:v|\.\w+?)$/) {
                print "Government\t$host ($k)\n";
        }
        elsif ($host =~ m/\.co(?:m|\.\w+?)$/) {
                print "Company\t$host ($k)\n";
        }
        elsif ($host =~ m/\.or(?:g|\.\w+?)$/) {
                print "Organization\t$host ($k)\n";
        }
        elsif ($host =~ m/\.ed(?:u|\w+?)$/) {
                print "Education\t$host ($k)\n";
        }
        elsif ($host =~ m/\.ac\.jp$/) {
                print "Univ(JP)\t$host ($k)\n";
        }
        elsif ($host =~ m/\.mil$/) {
                print "MILITARY\t$host ($k)\n";
        }
        elsif ($host =~ m/\.jp$/) {
                print "Japan\t$host ($k)\n";
        }
        else {
                print "Unknown\t$host ($k)\n";
        }
}