Firewall - Nat
Hi i need some help making an iptables script that does the following...
1) eth0 has 4 extern ips
eth0 -> 192.168.0.50 (nic 0)
eth0:eth2 -> 192.168.0.200
eth0:eth3 -> 192.168.0.201
eth0:eth4 -> 192.168.0.202
eth1 -> 192.168.0.1 (internal network) (nic 1)
2) On eth1 there is a 5 port switch which has 4 different webservers connected to it.
webserver 1 -> 172.168.0.2
wbeserver 2 -> 172.168.0.3
webserver 3 -> 172.168.0.4
webserver 3 -> 172.168.0.5
3) On eth0 the only incoming traffic is allowed on port 21,23 and 80.from 192.168.0.0/255.255.255.0 network.
All outgoing traffic is allowed.
4) On eth1 all traffic is allowed both ways.
5) This is the most important rule i need.
192.168.0.50:80 -> 172.168.0.2:80
192.168.0.200:80 -> 172.168.0.3:80
192.168.0.201:80 -> 172.168.0.4:80
192.168.0.202:80 -> 172.168.0.5:80This what i have so far but it does not work at all. I'm not sure what is wrong with it.
+++++++++++++++++++++++++++++
Hardware is TS-5500
cpu elan (486 DX/4-WD) 66Mhz
++++++++++++++++++++++++++++
=========================================================================================
#!/bin/sh
NETACCEPT=192.168.0.0/255.255.255.0
NAT=yes
TEST=start
case "$TEST" in
'start')
if [ -x /usr/bin/logger ]; then
logger -p info "Firewall Starting"
fi
FWD=cat /proc/sys/net/ipv4/ip_forward echo "0" > /proc/sys/net/ipv4/ip_forward echo "30" > /proc/sys/net/ipv4/tcp_fin_timeout echo "1800" > /proc/sys/net/ipv4/tcp_keepalive_intvl
iptables -P OUTPUT ACCEPT
iptables -P INPUT DROP
iptables -P FORWARD DROP
cat /proc/net/ip_tables_names | while read table; do iptables -t $table -L -n | while read c chain rest; do
if test "X$c" = "XChain" ; then
iptables -t $table -F $chain
fi
done
iptables -t $table -X
done
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A OUTPUT -m state --state ESTABLISHED,RELATED -j ACCEPT iptables -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
#
# Interface Rule #0 for ETH0
#
iptables -N ETH0
iptables -A OUTPUT -o eth0 -m state --state NEW -j ETH0 iptables -A FORWARD -o eth0 -m state --state NEW -j ETH0 iptables -A ETH0 -j ACCEPT
#
# Interface Rule #1 for ETH0
#
iptables -N TELNET
iptables -A INPUT -i eth0 -p tcp -m state --state NEW -s $NETACCEPT
--destination-port 23 -j TELNET
iptables -A FORWARD -i eth0 -p tcp -m state --state NEW -s $NETACCEPT
--destination-port 23 -j TELNET
iptables -A INPUT -i eth0 -p udp -m state --state NEW -s $NETACCEPT
--destination-port 23 -j TELNET
iptables -A FORWARD -i eth0 -p udp -m state --state NEW -s $NETACCEPT--destination-port 23 -j TELNET
iptables -A TELNET -j LOG --log-level info --log-prefix "TELNET_IN : "
iptables -A TELNET -j ACCEPT
#
# Interface Rule #2 for ETH0
#
iptables -N FTP
iptables -A INPUT -i eth0 -p tcp -m state --state NEW -s $NETACCEPT
--destination-port 21 -j FTP
iptables -A FORWARD -i eth0 -p tcp -m state --state NEW -s $NETACCEPT
--destination-port 21 -j FTP
iptables -A INPUT -i eth0 -p udp -m state --state NEW -s $NETACCEPT
--destination-port 21 -j FTP
iptables -A FORWARD -i eth0 -p udp -m state --state NEW -s $NETACCEPT--destination-port 21 -j FTP
iptables -A FTP -j LOG --log-level info --log-prefix "FTP_IN : "
iptables -A FTP -j ACCEPT
#
# Interface Rule #3 for ETH0
#
iptables -N WWW
iptables -A INPUT -i eth0 -p tcp -m state --state NEW -s $NETACCEPT
--destination-port 80 -j WWW
iptables -A FORWARD -i eth0 -p tcp -m state --state NEW -s $NETACCEPT
--destination-port 80 -j WWW
iptables -A INPUT -i eth0 -p udp -m state --state NEW -s $NETACCEPT
--destination-port 80 -j WWW
iptables -A FORWARD -i eth0 -p udp -m state --state NEW -s $NETACCEPT--destination-port 80 -j WWW
iptables -A WWW -j LOG --log-level info --log-prefix "WWW_IN : "
iptables -A WWW -j ACCEPT
#
# Interface Rule #0 for LO
#
iptables -N LO
iptables -A INPUT -i lo -m state --state NEW -j LO
iptables -A FORWARD -i lo -m state --state NEW -j LO
iptables -A OUTPUT -o lo -m state --state NEW -j LO
iptables -A FORWARD -o lo -m state --state NEW -j LO
iptables -A LO -j ACCEPT#
# Interface Rule #0 for ETH1
#
iptables -N ETH1
iptables -A INPUT -i eth1 -m state --state NEW -j ETH1
iptables -A FORWARD -i eth1 -m state --state NEW -j ETH1
iptables -A OUTPUT -o eth1 -m state --state NEW -j ETH1
iptables -A FORWARD -o eth1 -m state --state NEW -j ETH1
iptables -A ETH1 -j ACCEPT#
# Final rules filter
#
iptables -A INPUT -j DROP
iptables -A OUTPUT -j ACCEPT
iptables -A FORWARD -j DROP echo "$FWD" > /proc/sys/net/ipv4/ip_forward
if [ -x /usr/bin/logger ]; then
logger -p info "Filter Done"
fi
#
# rules nat
#
if [ $NAT == "yes" ]; then
#
ifconfig eth0:eth2 192.168.0.200 netmask 255.255.255.0 up
ifconfig eth0:eth3 192.168.0.201 netmask 255.255.255.0 up
ifconfig eth0:eth4 192.168.0.202 netmask 255.255.255.0 up
#
iptables -t nat -A POSTROUTING -o eth0 -s 172.168.0.0/255.255.255.0 -d0/0 -j MASQUERADE
iptables -t nat -A PREROUTING -p udp -i eth0 -d 192.168.0.50 --dport 80
-j DNAT --to 172.168.0.2:80
iptables -t nat -A PREROUTING -p tcp -i eth0 -d 192.168.0.50 --dport 80-j DNAT --to 172.168.0.2:80
iptables -t nat -A PREROUTING -p udp -i eth0 -d 192.168.0.200 --dport 80
-j DNAT --to 172.168.0.3:80
iptables -t nat -A PREROUTING -p tcp -i eth0 -d 192.168.0.200 --dport 80-j DNAT --to 172.168.0.3:80
iptables -t nat -A PREROUTING -p udp -i eth0 -d 192.168.0.201 --dport 80
-j DNAT --to 172.168.0.4:80
iptables -t nat -A PREROUTING -p tcp -i eth0 -d 192.168.0.201 --dport 80-j DNAT --to 172.168.0.4:80
iptables -t nat -A PREROUTING -p udp -i eth0 -d 192.168.0.202 --dport 80
-j DNAT --to 172.168.0.5:80
iptables -t nat -A PREROUTING -p tcp -i eth0 -d 192.168.0.202 --dport 80-j DNAT --to 172.168.0.5:80
if [ -x /usr/bin/logger ]; then
logger -p info "Nat Done"
fi
fi
;;
'stop')
logger -p info "Firewall Is Down"
iptables -P OUTPUT ACCEPT
iptables -P INPUT ACCEPT
iptables -P FORWARD ACCEPT
cat /proc/net/ip_tables_names | while read table; do iptables -t $table -L -n | while read c chain rest; do if test "X$c" = "XChain" ; then
iptables -t $table -F $chain
fi
done
iptables -t $table -X
done
;;
*)
echo "usage $0 start|stop"
;;
esac
=============================================================================================
Help Please.
I'm not sure if if have to repeat all rules for eth2,eth3,eth4 .
Signature · 1 line
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