-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi, I've just set up iptables based on Oskar Andreasson's template (eth0/eth1, http://www.faqs.org/docs/iptables) but find I can't connect to the server. Luckily 'flush-iptables' is to hand.
I've added line 88 to log tcp options according to 'man psad'. Could this have done it ? I'd be grateful for any constructive comment (apologies Oskar). Adam Bogacki, [EMAIL PROTECTED] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQFClZLY18X1Fk5VORARAs74AJoDJsuVU95SZS1oD3hQzvPB0FzZagCcDDYS o0zjtMb5sPKQEuhf4Zylz54= =6Xrk -----END PGP SIGNATURE-----
#!/bin/sh INET_IP="192.168.0.1" INET_IFACE="eth0" INET_BROADCAST="192.168.0.100" LAN_IP="192.168.0.2" LAN_IP_RANGE="192.168.0.0/16" LAN_IFACE="eth1" LO_IFACE="lo" LO_IP="127.0.0.1" IPTABLES="/usr/sbin/iptables" /sbin/depmod -a /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 echo "1" > /proc/sys/net/ipv4/ip_forward iptables -P INPUT DROP iptables -P OUTPUT DROP iptables -P FORWARD DROP iptables -N bad_tcp_packets iptables -N allowed iptables -N tcp_packets iptables -N udp_packets iptables -N icmp_packets 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 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 iptables -A tcp_packets -p TCP -s 0/0 --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 113 -j allowed #$IPTABLES -A udp_packets -p UDP -s 0/0 --destination-port 53 -j ACCEPT #$IPTABLES -A udp_packets -p UDP -s 0/0 --destination-port 123 -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 icmp_packets -p ICMP -s 0/0 --icmp-type 8 -j ACCEPT iptables -A icmp_packets -p ICMP -s 0/0 --icmp-type 11 -j ACCEPT iptables -A INPUT -p tcp -j bad_tcp_packets 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 iptables -A INPUT -p UDP -i $LAN_IFACE --dport 67 --sport 68 -j ACCEPT 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 iptables -A INPUT -m limit --limit 3/minute --limit-burst 3 -j LOG \ --log-level DEBUG --log-prefix "IPT INPUT packet died: " iptables -A FORWARD -p tcp -j bad_tcp_packets iptables -A FORWARD -i $LAN_IFACE -j ACCEPT iptables -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT iptables -A FORWARD -p tcp -j LOG --log-tcp-options iptables -A FORWARD -m limit --limit 3/minute --limit-burst 3 -j LOG \ --log-level DEBUG --log-prefix "IPT FORWARD packet died: " iptables -A OUTPUT -p tcp -j bad_tcp_packets 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 iptables -A OUTPUT -m limit --limit 3/minute --limit-burst 3 -j LOG \ --log-level DEBUG --log-prefix "IPT OUTPUT packet died: " iptables -t nat -A POSTROUTING -o $INET_IFACE -j SNAT --to-source $INET_IP
