Iptables Tutorial 1.1.19
Шрифт:
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# From LAN Interface to LAN firewall IP
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$IPTABLES -A INPUT -p ALL -i $LAN_IFACE -d $LAN_IP -j ACCEPT
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# From Localhost interface to Localhost IP's
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$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 $INET_IP -j ACCEPT
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# Special rule for DHCP requests from LAN, which are not caught properly
# otherwise.
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$IPTABLES -A INPUT -p UDP -i $LAN_IFACE –dport 67 –sport 68 -j ACCEPT
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# All established and related packets incoming from the internet to the
# firewall
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$IPTABLES -A INPUT -p ALL -d $INET_IP -m state –state ESTABLISHED,RELATED \
–j ACCEPT
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# In Microsoft Networks you will be swamped by broadcasts. These lines
# will prevent them from showing up in the logs.
#
#$IPTABLES -A INPUT -p UDP -i $INET_IFACE -d $INET_BROADCAST \
#–destination-port 135:139 -j DROP
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# If we get DHCP requests from the Outside of our network, our logs will
# be swamped as well. This rule will block them from getting logged.
#
#$IPTABLES -A INPUT -p UDP -i $INET_IFACE -d 255.255.255.255 \
#–destination-port 67:68 -j DROP
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# If you have a Microsoft Network on the outside of your firewall, you may
# also get flooded by Multicasts. We drop them so we do not get flooded by
# logs
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#$IPTABLES -A INPUT -i $INET_IFACE -d 224.0.0.0/8 -j DROP
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# Log weird packets that don't match the above.
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$IPTABLES -A INPUT -m limit –limit 3/minute –limit-burst 3 -j LOG \
–log-level DEBUG –log-prefix "IPT INPUT packet died: "
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# 4.1.5 FORWARD chain
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#
# Bad TCP packets we don't want
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$IPTABLES -A FORWARD -p tcp -j bad_tcp_packets
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# DMZ section
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# General rules
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$IPTABLES -A FORWARD -i $DMZ_IFACE -o $INET_IFACE -j ACCEPT
$IPTABLES -A FORWARD -i $INET_IFACE -o $DMZ_IFACE -m state \
–state ESTABLISHED,RELATED -j ACCEPT
$IPTABLES -A FORWARD -i $LAN_IFACE -o $DMZ_IFACE -j ACCEPT
$IPTABLES -A FORWARD -i $DMZ_IFACE -o $LAN_IFACE -m state \
–state ESTABLISHED,RELATED -j ACCEPT
#
# HTTP server
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$IPTABLES -A FORWARD -p TCP -i $INET_IFACE -o $DMZ_IFACE -d $DMZ_HTTP_IP \
–dport 80 -j allowed
$IPTABLES -A FORWARD -p ICMP -i $INET_IFACE -o $DMZ_IFACE -d $DMZ_HTTP_IP \
–j icmp_packets
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# DNS server
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$IPTABLES -A FORWARD -p TCP -i $INET_IFACE -o $DMZ_IFACE -d $DMZ_DNS_IP \
–dport 53 -j allowed
$IPTABLES -A FORWARD -p UDP -i $INET_IFACE -o $DMZ_IFACE -d $DMZ_DNS_IP \
–dport 53 -j ACCEPT
$IPTABLES -A FORWARD -p ICMP -i $INET_IFACE -o $DMZ_IFACE -d $DMZ_DNS_IP \
–j icmp_packets
#
# LAN section
#
$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.
#
$IPTABLES -A FORWARD -m limit –limit 3/minute –limit-burst 3 -j LOG \
–log-level DEBUG –log-prefix "IPT FORWARD packet died: "
#
# 4.1.6 OUTPUT chain
#
#
# Bad TCP packets we don't want.
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$IPTABLES -A OUTPUT -p tcp -j bad_tcp_packets
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# 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.
#
$IPTABLES -A OUTPUT -m limit –limit 3/minute –limit-burst 3 -j LOG \
–log-level DEBUG –log-prefix "IPT OUTPUT packet died: "
######
# 4.2 nat table
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# 4.2.1 Set policies
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# 4.2.2 Create user specified chains
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# 4.2.3 Create content in user specified chains
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# 4.2.4 PREROUTING chain
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$IPTABLES -t nat -A PREROUTING -p TCP -i $INET_IFACE -d $HTTP_IP –dport 80 \
–j DNAT –to-destination $DMZ_HTTP_IP
$IPTABLES -t nat -A PREROUTING -p TCP -i $INET_IFACE -d $DNS_IP –dport 53 \
–j DNAT –to-destination $DMZ_DNS_IP
$IPTABLES -t nat -A PREROUTING -p UDP -i $INET_IFACE -d $DNS_IP –dport 53 \
–j DNAT –to-destination $DMZ_DNS_IP
#
# 4.2.5 POSTROUTING chain
#
#
# Enable simple IP Forwarding and Network Address Translation