I have a LAN with Windows XP clients and cablemodem exit to Internet thru a router Debian Woody with iptables. I need that one of the clients (192.168.111.2) can to download and upload files with eMule. I applied in the router the iptables rules given by Oskar Andreason in their tutorial and I opened the ports (tcp and udp) 4661, 4662, 4665, 4672, 4711. BUT the eMule continues giving Low ID to client. With an external ports-scan on the router I find that these ports continue presenting to eMule as stealth, in spite of the fact that I opened them. I need to know if what I made to open these ports is well. Please you could revise the rules that I paste below and tell me if they are OK??? Because if they are OK my ISP is filtering the ports corresponding to the eMule. -----------------------------paste iptables rules from here----------- #!/bin/sh /etc/init.d/iptables clear # 1.1 Internet Configuration. # INET_IFACE="eth0" INET_IP=$(ipofif eth0) # # 1.1.1 DHCP # # # 1.1.2 PPPoE # # # 1.2 Local Area Network configuration. # # your LAN's IP range and localhost IP. /24 means to only use the first 24 # bits of the 32 bit IP address. the same as netmask 255.255.255.0 # LAN_IFACE="eth1" LAN_IP="192.168.111.1" LAN_IP_RANGE="192.168.111.0/8" # # 1.3 DMZ Configuration. # # # 1.4 Localhost Configuration. # LO_IFACE="lo" LO_IP="127.0.0.1" # # 1.5 IPTables Configuration. # IPTABLES="/sbin/iptables" # # 1.6 Other Configuration. # ########################################################################### # # 2. Module loading. # # # Needed to initially load modules # # #/sbin/depmod -a # # # 2.1 Required modules # # #/sbin/modprobe ip_tables #/sbin/modprobe ip_conntrack #/sbin/modprobe iptable_filter #/sbin/modprobe iptable_mangle #/sbin/modprobe iptable_nat #/sbin/modprobe ipt_LOG #/sbin/modprobe ipt_limit #/sbin/modprobe ipt_state # # 2.2 Non-Required modules # #/sbin/modprobe ipt_owner #/sbin/modprobe ipt_REJECT #/sbin/modprobe ipt_MASQUERADE #/sbin/modprobe ip_conntrack_ftp #/sbin/modprobe ip_conntrack_irc #/sbin/modprobe ip_nat_ftp #/sbin/modprobe ip_nat_irc ########################################################################### # # 3. /proc set up. # # # 3.1 Required proc configuration # #echo "1" > /proc/sys/net/ipv4/ip_forward # # 3.2 Non-Required proc configuration # #echo "1" > /proc/sys/net/ipv4/conf/all/rp_filter #echo "1" > /proc/sys/net/ipv4/conf/all/proxy_arp #echo "1" > /proc/sys/net/ipv4/ip_dynaddr ########################################################################### # # 4. rules set up. # ###### # 4.1 Filter table # # # 4.1.1 Set policies # $IPTABLES -P INPUT DROP $IPTABLES -P OUTPUT DROP $IPTABLES -P FORWARD DROP # # 4.1.2 Create userspecified chains # # # 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 # # 4.1.3 Create content in userspecified chains # # # 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 $LAN_IP_RANGE --dport 21 -j allowed #$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 22 -j allowed #$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 80 -j allowed $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 53 -j ACCEPT #$IPTABLES -A udp_packets -p UDP -s 0/0 --destination-port 23 -j ACCEPT #$IPTABLES -A udp_packets -p UDP -s 0/0 --destination-port 80 -j ACCEPT $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 $IPTABLES -A udp_packets -p UDP -s 0/0 --destination-port 4672 -j ACCEPT # # In Microsoft Networks you will be swamped by broadcasts. These lines # will prevent them from showing up in the logs. # #$IPTABLES -A udp_packets -p UDP -i $INET_IFACE -d $INET_BROADCAST \ #--destination-port 135:139 -j DROP # # 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 # # 4.1.4 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 $INET_IP -j ACCEPT # # Special rule for DHCP requests from LAN, which are not caught properly # otherwise. # #$IPTABLES -A INPUT -p UDP -i $LAN_IFACE --dport 67 --sport 68 -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 $INET_IFACE -j icmp_packets # # If you have a Microsoft Network on the outside of your firewall, you may # also get flooded by Multicasts. We drop them so we do not get flooded by # logs # #$IPTABLES -A INPUT -i $INET_IFACE -d 224.0.0.0/8 -j DROP # # Log weird packets that don't match the above. # $IPTABLES -A INPUT -m limit --limit 3/minute --limit-burst 3 -j LOG \ --log-level DEBUG --log-prefix "IPT INPUT packet died: " # # 4.1.5 FORWARD chain # #$IPTABLES -t nat -A PREROUTING -p tcp -d $INET_IP --dport 80 -j DNAT --to-destination 192.168.111.2:80 $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 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 # # Bad TCP packets we don't want # $IPTABLES -A FORWARD -p tcp -j bad_tcp_packets # # Accept the packets we actually want to forward # $IPTABLES -A FORWARD -i $LAN_IFACE -j ACCEPT $IPTABLES -A FORWARD -m state --state ESTABLISHED,RELATED -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 # # # 4.2.1 Set policies # # # 4.2.2 Create user specified chains # # # 4.2.3 Create content in user specified chains # # # 4.2.4 PREROUTING chain # # # 4.2.5 POSTROUTING chain # # # Enable simple IP Forwarding and Network Address Translation # $IPTABLES -t nat -A POSTROUTING -o $INET_IFACE -j SNAT --to-source $INET_IP # # 4.2.6 OUTPUT chain # ###### # 4.3 mangle table #Mark paquetes segun IPs, para sfq (QoS)(ver script /etc/init.d/cbq.init) #$IPTABLES -A FORWARD -s 192.168.111.2 -t mangle -j MARK --set-mark 1 #$IPTABLES -A FORWARD -s 192.168.111.3 -t mangle -j MARK --set-mark 2 #$IPTABLES -A FORWARD -s 192.168.111.4 -t mangle -j MARK --set-mark 3 # # 4.3.1 Set policies # # # 4.3.2 Create user specified chains # # # 4.3.3 Create content in user specified chains # # # 4.3.4 PREROUTING chain # # # 4.3.5 INPUT chain # # # 4.3.6 FORWARD chain # # # 4.3.7 OUTPUT chain # # # 4.3.8 POSTROUTING chain # # #Guardando seteos en el inicio # /etc/init.d/iptables save active -----------------end paste------------------------------------------ Thank you for the help and the patience. . . ;) Regards Richard Buenos Aires Argentina
