I have a Intranet with clients Win XP and a server-router for exit to Internet Debian Woody with iptables making NAT. I want that a client (host 192.168.111.2) can download and upload files with eMule and I want that this host doesn't have Low ID of eMule. For that I have opened the ports and redirected the packages TCP/UDP toward the client.All the rules are copied from Oskar Andreasson tutorial, except those of FORWARD AND PREROUTING referred to eMule ports. But I'm not sure if I made it well. You could give me your opinions???? I want to open up exclusively the necessary ports but I want to maintain the highest security in the rest. I paste a copy of the iptables script below so that see it (maximize the window to see better the script) --------------------------paste-------------------------------------------------------------------------------- -------------------------------------------------- #!/bin/sh /etc/init.d/iptables clear INET_IFACE="eth0" INET_IP=$(ipofif eth0) LAN_IFACE="eth1" LAN_IP="192.168.111.1" LAN_IP_RANGE="192.168.111.0/8" LO_IFACE="lo" LO_IP="127.0.0.1" IPTABLES="/sbin/iptables" $IPTABLES -P INPUT DROP $IPTABLES -P OUTPUT DROP $IPTABLES -P FORWARD DROP # # Create chain for bad tcp packets # $IPTABLES -N bad_tcp_packets # # Create separate chains for ICMP, TCP and UDP to traverse # $IPTABLES -N allowed $IPTABLES -N tcp_packets $IPTABLES -N udp_packets $IPTABLES -N icmp_packets # # bad_tcp_packets chain # $IPTABLES -A bad_tcp_packets -p tcp --tcp-flags SYN,ACK SYN,ACK \ -m state --state NEW -j REJECT --reject-with tcp-reset $IPTABLES -A bad_tcp_packets -p tcp ! --syn -m state --state NEW -j LOG \ --log-prefix "New not syn:" $IPTABLES -A bad_tcp_packets -p tcp ! --syn -m state --state NEW -j DROP # # allowed chain # $IPTABLES -A allowed -p TCP --syn -j ACCEPT $IPTABLES -A allowed -p TCP -m state --state ESTABLISHED,RELATED -j ACCEPT $IPTABLES -A allowed -p TCP -j DROP # # TCP rules # $IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 4661 -j allowed $IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 4662 -j allowed $IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 4711 -j allowed # # UDP ports # $IPTABLES -A udp_packets -p UDP -s 0/0 --destination-port 2074 -j ACCEPT $IPTABLES -A udp_packets -p UDP -s 0/0 --destination-port 4000 -j ACCEPT $IPTABLES -A udp_packets -p UDP -s 0/0 --destination-port 4665 -j ACCEPT $IPTABLES -A udp_packets -p UDP -s 0/0 --destination-port 4672 -j ACCEPT # # If we get DHCP requests from the Outside of our network, our logs will # be swamped as well. This rule will block them from getting logged. # $IPTABLES -A udp_packets -p UDP -i $INET_IFACE -d 255.255.255.255 \ --destination-port 67:68 -j DROP # # ICMP rules # $IPTABLES -A icmp_packets -p ICMP -s 0/0 --icmp-type 8 -j DROP $IPTABLES -A icmp_packets -p ICMP -s 0/0 --icmp-type 11 -j DROP # # INPUT chain # # Bad TCP packets we don't want. # $IPTABLES -A INPUT -p tcp -j bad_tcp_packets # # Rules for special networks not part of the Internet # $IPTABLES -A INPUT -p ALL -i $LAN_IFACE -s $LAN_IP_RANGE -j ACCEPT $IPTABLES -A INPUT -p ALL -i $LO_IFACE -s $LO_IP -j ACCEPT $IPTABLES -A INPUT -p ALL -i $LO_IFACE -s $LAN_IP -j ACCEPT $IPTABLES -A INPUT -p ALL -i $LO_IFACE -s $INET_IP -j ACCEPT # # Rules for incoming packets from the internet. # $IPTABLES -A INPUT -p ALL -d $INET_IP -m state --state ESTABLISHED,RELATED \ -j ACCEPT $IPTABLES -A INPUT -p TCP -i $INET_IFACE -j tcp_packets $IPTABLES -A INPUT -p UDP -i $INET_IFACE -j udp_packets $IPTABLES -A INPUT -p ICMP -i $INET_IFACE -j icmp_packets # # Log weird packets that don't match the above. # $IPTABLES -A INPUT -m limit --limit 3/minute --limit-burst 3 -j LOG \ --log-level DEBUG --log-prefix "IPT INPUT packet died: " # # 4.1.5 FORWARD chain # # # Bad TCP packets we don't want # $IPTABLES -A FORWARD -p tcp -j bad_tcp_packets # # Accept the packets we actually want to forward (Ports 4661, 4662, 4711, 4665, 4672 are for eMule) # $IPTABLES -A FORWARD -i $LAN_IFACE -j ACCEPT $IPTABLES -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT $IPTABLES -A FORWARD -p tcp --dport 4661 -j ACCEPT $IPTABLES -A FORWARD -p tcp --dport 4662 -j ACCEPT $IPTABLES -A FORWARD -p tcp --dport 4711 -j ACCEPT $IPTABLES -A FORWARD -p udp --dport 4000 -j ACCEPT $IPTABLES -A FORWARD -p udp --dport 4665 -j ACCEPT $IPTABLES -A FORWARD -p udp --dport 4672 -j ACCEPT # # Log weird packets that don't match the above. # $IPTABLES -A FORWARD -m limit --limit 3/minute --limit-burst 3 -j LOG \ --log-level DEBUG --log-prefix "IPT FORWARD packet died: " # # 4.1.6 OUTPUT chain # # # Bad TCP packets we don't want. # $IPTABLES -A OUTPUT -p tcp -j bad_tcp_packets # # Special OUTPUT rules to decide which IP's to allow. # $IPTABLES -A OUTPUT -p ALL -s $LO_IP -j ACCEPT $IPTABLES -A OUTPUT -p ALL -s $LAN_IP -j ACCEPT $IPTABLES -A OUTPUT -p ALL -s $INET_IP -j ACCEPT # # Log weird packets that don't match the above. # $IPTABLES -A OUTPUT -m limit --limit 3/minute --limit-burst 3 -j LOG \ --log-level DEBUG --log-prefix "IPT OUTPUT packet died: " ###### # 4.2 nat table # # # 4.2.4 PREROUTING chain (Ports 4661, 4662, 4711, 4665, 4672 for eMule forward to host 192.168.111.2, the one that running eMule) # $IPTABLES -t nat -A PREROUTING -p tcp -d $INET_IP --dport 4661 -j DNAT --to-destination 192.168.111.2:4661 $IPTABLES -t nat -A PREROUTING -p tcp -d $INET_IP --dport 4662 -j DNAT --to-destination 192.168.111.2:4662 $IPTABLES -t nat -A PREROUTING -p tcp -d $INET_IP --dport 4711 -j DNAT --to-destination 192.168.111.2:4711 $IPTABLES -t nat -A PREROUTING -p UDP -d $INET_IP --dport 4000 -j DNAT --to-destination 192.168.111.2:4000 $IPTABLES -t nat -A PREROUTING -p UDP -d $INET_IP --dport 4665 -j DNAT --to-destination 192.168.111.2:4665 $IPTABLES -t nat -A PREROUTING -p UDP -d $INET_IP --dport 4672 -j DNAT --to-destination 192.168.111.2:4672 # # Enable Network Address Translation # $IPTABLES -t nat -A POSTROUTING -o $INET_IFACE -j SNAT --to-source $INET_IP # #Save settings # /etc/init.d/iptables save active -------------------------------------------------------------------end paste------------------------------------------------------------------------------------ Thanks to all to help me Regards Richard
