#!/bin/sh

iptables=/sbin/iptables
# Set this to be the outside interface of your fw.
interface="eth0"

SPAMMER[0]="210.0.0.0/8"
SPAMMER[1]="211.0.0.0/8"
SPAMMER[2]="212.0.0.0/8"
SPAMMER[3]="202.0.0.0/8"
SPAMMER[4]="194.0.0.0/8"
SPAMMER[5]="222.0.0.0/8"
SPAMMER[6]="221.0.0.0/8"
SPAMMER[7]="69.34.0.0/16"
SPAMMER[8]="65.40.172.0/23"
SPAMMER[9]="65.40.168.0/22"
SPAMMER[10]="65.40.160.0/21"

cnt=0
for network in ${SPAMMER[@]}; do

    $iptables -A FORWARD -s $network -i $interface -p tcp -m tcp --dport 25 \
       -j LOG --log-prefix "$network SPAMMER: "
    $iptables -A FORWARD -s $network -i $interface -p tcp -m tcp --dport 25 \
       -j REJECT --reject-with tcp-reset

    let cnt+=1
done