Category: linux

squid in 3169 portundan çalıştığını düşünürsek aşağıdaki kurallar bütünü işimizi görecektir.

#!/bin/sh
# squid server IP
SQUID_SERVER=`ifconfig eth0 | sed -ne 's/.*inet addr:([^ ]*).*/1/p'`
# Interface connected to Internet
INTERNET="eth0"
# Interface connected to LAN
LAN_IN="eth0"
# Squid port
SQUID_PORT="3128"
# DO NOT MODIFY BELOW
# Clean old firewall
iptables -F
iptables -X
iptables -t nat -F
iptables -t nat -X
iptables -t mangle -F
iptables -t mangle -X
# Load IPTABLES modules for NAT and IP conntrack support
modprobe ip_conntrack
modprobe ip_conntrack_ftp
# For win xp ftp client
#modprobe ip_nat_ftp
echo 1 > /proc/sys/net/ipv4/ip_forward
# Setting default filter policy
iptables -P INPUT DROP
iptables -P OUTPUT ACCEPT
# Unlimited access to loop back
iptables -A INPUT -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT
# Allow UDP, DNS and Passive FTP
iptables -A INPUT -i $INTERNET -m state --state ESTABLISHED,RELATED -j ACCEPT
# set this system as a router for Rest of LAN
iptables --table nat --append POSTROUTING --out-interface $INTERNET -j MASQUERADE
iptables --append FORWARD --in-interface $LAN_IN -j ACCEPT
# unlimited access to LAN
iptables -A INPUT -i $LAN_IN -j ACCEPT
iptables -A OUTPUT -o $LAN_IN -j ACCEPT
# DNAT port 80 request comming from LAN systems to squid 3128 ($SQUID_PORT) aka transparent proxy
iptables -t nat -A PREROUTING -i $LAN_IN -p tcp --dport 80 -j DNAT --to $SQUID_SERVER:$SQUID_PORT
#iptables -t nat -A PREROUTING -i $LAN_IN -p tcp --dport 443 -j DNAT --to $SQUID_SERVER:3130

# if it is same system
iptables -t nat -A PREROUTING -i $INTERNET -p tcp --dport 80 -j REDIRECT --to-port $SQUID_PORT
#iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 443 -j REDIRECT --to-port 3130
# DROP everything and Log it
iptables -A INPUT -j LOG
iptables -A INPUT -j DROP

iptables -A OUTPUT -i $INTERNET -p tcp -m multiport --dports 21,22,110,25,143,587,3169 -m state --state NEW -j ACCEPT
iptables -A INPUT -i $INTERNET -p tcp -m multiport --dports 21,22,110,25,143,587,3169 -m state --state NEW -j ACCEPT
iptables -A OUTPUT -p icmp --icmp-type echo-request -j ACCEPT
iptables -A INPUT -p icmp --icmp-type echo-reply -j ACCEPT