slightly upgraded the script to monitor multiple logs and automatically remove the ban by the time, sends mail and logging all ban incidents:

#!/usr/bin/perl -w

use strict;
use warnings;
use Sys::Syslog qw(:DEFAULT setlogsock);
use POSIX qw(strftime);

my $pattern = "\"GET \/ HTTP\/"; # request index page pattern
my @httpd_log = </var/log/httpd/domains/*.log>;
my $ok = "1000"; # allowed connections per ip for $check_period
my $check_period = 1; # check period in hours

my $date = strftime("%d/%b/%Y:%H",localtime(time-$check_period*3600));
my (%ips, $ip, $start);
my (%ips_ban, $ip_ban, $time);

my $end_time = strftime("%H", localtime(time+$check_period*3600));
my $start_time;

setlogsock('unix');
openlog("http_block", 'ndelay', 'LOG_SECURITY');
syslog("info","http_block started using ipfw \n");
system("/sbin/ipfw table 2 flush");

open my $pipe, "-|", "/usr/bin/tail", "-f", @httpd_log
    or die "could not start tail on file.log: $!";

while (<$pipe>) {
  $date = strftime("%d/%b/%Y:%H",localtime(time-$check_period*3600)); 
    next unless m/$date/ || $start; # skipping old records
    $start=1;
    if (/^(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}).*$pattern/go) {
            $ips{$1}++;
    }

 foreach $ip (keys %ips) {
  if ($ips{$ip} >= $ok) {
    if (exists $ips_ban{$ip}) {
 syslog("info", "BLOCKING $ip with $ips{$ip} conn not working!!!\n");
        }
        if (not exists $ips_ban{$ip}) {
            #system("/sbin/pfctl -t bots -T add $ip");  
            #system("/sbin/iptables -A INPUT -s $ip -j REJECT"); 
        system("/sbin/ipfw table 2 add $ip");
        syslog("info", "BLOCKING $ip with $ips{$ip} conn \n");
                system("echo 'BLOCKING $ip with $ips{$ip} conn by http
+_block '|mail -s 'BLOCKING $ip by http_block' root");
        }
        $ips_ban{$ip} = strftime("%H", localtime(time));
        delete $ips{$ip};
        next;
        }
    }

    $start_time = strftime("%H", localtime(time));
    if ($end_time <= $start_time) {
    foreach $ip (keys %ips_ban) {
        if ($ips_ban{$ip}+1 <= $start_time) {
        system("/sbin/ipfw table 2 delete $ip");
        syslog("info", "UNBLOCKED $ip \n");
        system("echo 'UNBLOCKED $ip by http_block'|mail -s 'UNBLOCKED 
+$ip by http_block' root");
        delete $ips_ban{$ip};
        }
    }
    $end_time = strftime("%H", localtime(time+$check_period*3600));
    }
};

closelog;
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