How to Implement iptables port ing

Iptables port ingThe implementation steps are as follows:

I. Environment and functions to be implemented

The network settings of PC1 are as follows:

Eth0 192.168.0.29 Intranet

Eth1 219.239.11.22 Internet

The Network Setting of PC2 is 192.168.0.21 intranet.

The function we need to implement is to map port 8080 of PC1 to port 80 of PC2, that is, access

Http: // 219.239.11.22: 8080

You can access the WEB service on pc2.

　II. Implementation steps

1. First, the net. ipv4.ip _ forward = 1 in the/etc/sysctl. conf configuration file is 0 by default.

This allows iptalbes FORWARD.

2. There is an iptables file in the/etc/rc. d/init. d directory. The format is as follows:

Usage:./iptables {start | stop | restart | condrestart | status | panic | save}

Equivalent to service iptables {....}

Stop the iptables service, clear previous rules, and save disks.

Go to the/etc/rc. d/init. d directory and run

./Iptables stop

Iptalbes-F

Iptalbes-X

Iptalbes-Z

./Iptables save

3. reconfigure rules

Iptables-t nat-a prerouting-d 219.239.11.22-p tcp-m tcp -- dport 8080-j DNAT -- to-destination 192.168.0.21: 80

Iptables-t nat-a postrouting-d 192.168.0.21-p tcp-m tcp -- dport 80-j SNAT -- to-source 192.168.0.29

Iptables-a forward-o eth0-d 192.168.0.21-p tcp-dport 80-j ACCEPT

Iptables-a forward-I eth0-s 192.168.0.21-p tcp-sport 80-j ACCEPT

For more information about dnat snat, see help.

4. New rule Disks

./Iptables save

The rules are stored in the/etc/sysconfig/iptables file. If you are familiar with this file

Directly modifying the content here is also equivalent to entering the rule using the command line method.

5. Start the iptables service.

./Iptables start

There is a package flow in the/proc/net/ip_conntrack file, as shown below

Tcp 6 53 TIME_WAIT src =.../221.122.59.2 dst = 219.239.11.22 sport = 7958 dport = 8080 packets = 9 bytes = 1753

Src =.../172.18.10.205 dst = 172.18.10.212 sport = 80 dport = 7958 packets = 9 bytes = 5777 [ASSURED] use = 1

Through the introduction of this article, we can clearly see every step of iptables port ing implementation! Hope to help you!

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