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 -> 172.168.0.5:80
This 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 $NETACCEPT
--destination-port 80 -j WWW iptables -A WWW -j LOG --log-level info --log-prefix "WWW_IN : "
iptables -A WWW -j ACCEPT# # Interface Rule #0 for LO #
iptables -N LO
iptables -A INPUT -i lo -m state --state NEW -j LO
iptables -A FORWARD -i lo -m state --state NEW -j LO
iptables -A OUTPUT -o lo -m state --state NEW -j LO
iptables -A FORWARD -o lo -m state --state NEW -j LO
iptables -A LO -j ACCEPT# # Interface Rule #0 for ETH1 #
iptables -N ETH1
iptables -A INPUT -i eth1 -m state --state NEW -j ETH1
iptables -A FORWARD -i eth1 -m state --state NEW -j ETH1
iptables -A OUTPUT -o eth1 -m state --state NEW -j ETH1
iptables -A FORWARD -o eth1 -m state --state NEW -j ETH1
iptables -A ETH1 -j ACCEPT
# # Final rules filter #
iptables -A INPUT -j DROP
iptables -A OUTPUT -j ACCEPT
iptables -A FORWARD -j DROPecho "$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 -d
0/0 -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 .--
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