iptables - Setting Example #42013/07/29 |
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This is an Example of setting iptables on the Server below.
Internet
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+----------+
-------| Router | ------------------------------------------------------------------
+----------+ | +----------+
| | 10.0.0.31| |
LAN(192.168.0.0/24) | LAN(10.0.0.0/24) +---------| Backend1 |
| | | | | +----------+
| +----------+ | +----------+ | |
--------------------| Router |-------------+----|-----------------------| PC |
192.168.0.2+----------+10.0.0.1 | | +----------+ | |
| | | | | | +----------+
| +----------+ | +---------| Backend2 |
| eth0| |eth1 | 10.0.0.32| |
+------| Server |-------------+ +----------+
192.168.0.80| |10.0.0.80
+----------+
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* DROP INPUT by Default
* ACCEPT OUTPUT by Default * DROP FORWARD by Default * ACCEPT Established Connection * ACCEPT the Connection from loopback * Forward the Packets to 22 on eth0 to the same port on Backend1 * Forward the Packets to 80 on eth0 to the same port on Backend2 * ACCEPT Ping Connection for 5 times per a minites from internal network(10.0.0.0/24) * ACCEPT SSH Connection from internal network(10.0.0.0/24) * ACCEPT Outgoing Packets through the Server from internal network(10.0.0.0/24) and translatte the source address |
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| [1] | Configure iptables |
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[root@dlp ~]#
vi iptables.sh #!/bin/bash trust_host='10.0.0.0/24' my_internal_ip='10.0.0.80' my_external_ip='192.168.0.80' listen_port_1='22' backend_host_1='10.0.0.31' backend_port_1='22' listen_port_2='80' backend_host_2='10.0.0.32' backend_port_2='80' echo 1 > /proc/sys/net/ipv4/ip_forward /sbin/iptables -F /sbin/iptables -t nat -F /sbin/iptables -X /sbin/iptables -P INPUT DROP /sbin/iptables -P OUTPUT ACCEPT /sbin/iptables -P FORWARD DROP /sbin/iptables -A FORWARD -i eth1 -o eth0 -s $trust_host -j ACCEPT /sbin/iptables -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT /sbin/iptables -A FORWARD -p tcp --dst $backend_host_1 --dport $backend_port_1 -j ACCEPT /sbin/iptables -A FORWARD -p tcp --dst $backend_host_2 --dport $backend_port_2 -j ACCEPT /sbin/iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT /sbin/iptables -A INPUT -s 127.0.0.1 -d 127.0.0.1 -j ACCEPT /sbin/iptables -A INPUT -p icmp --icmp-type echo-request -s $trust_host \ -d $my_internal_ip -m limit --limit 1/m --limit-burst 5 -j ACCEPT /sbin/iptables -A INPUT -p tcp -m state --state NEW -m tcp -s $trust_host \ -d $my_internal_ip --dport 22 -j ACCEPT /sbin/iptables -t nat -A POSTROUTING -o eth0 -s $trust_host -j MASQUERADE /sbin/iptables -t nat -A PREROUTING -p tcp --dst $my_external_ip --dport $listen_port_1 \ -j DNAT --to-destination $backend_host_1:$backend_port_1 /sbin/iptables -t nat -A POSTROUTING -p tcp --dst $backend_host_1 --dport $backend_port_1 \ -j SNAT --to-source $my_internal_ip /sbin/iptables -t nat -A PREROUTING -p tcp --dst $my_external_ip --dport $listen_port_2 \ -j DNAT --to-destination $backend_host_2:$backend_port_2 /sbin/iptables -t nat -A POSTROUTING -p tcp --dst $backend_host_2 --dport $backend_port_2 \ -j SNAT --to-source $my_internal_ip /etc/rc.d/init.d/iptables save /etc/rc.d/init.d/iptables restart sh iptables.sh iptables: Saving firewall rules to /etc/sysconfig/iptables: [ OK ] iptables: Flushing firewall rules: [ OK ] iptables: Setting chains to policy ACCEPT: filter [ OK ] iptables: Unloading modules: [ OK ] iptables: Applying firewall rules: ip_tables: (C) 2000-2006 Netfilter Core Team nf_conntrack version 0.5.0 (16384 buckets, 65536 max) [ OK ] |
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