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This article mainly introduces the configuration process of static NAT, dynamic NAT, PAT and port mapping in detail. It is easy to learn and is very suitable for beginners. Interested friends can refer to it.

Experimental requirements: use the host to access the Web80 port of the virtual machine using NAT address translation technology. It's all about the steps of live ammunition.

Experimental premise: turn on the server 2008 virtual machine and build a simple web service. Open the line in the GNS3 connection topology diagram and connect the host while connecting to the network card of the virtual machine.

Experiment step: the first step is to configure IP addresses on hosts and virtual machines. Then configure the IP address on the router and test whether the host can properly access the web service at this time.

Then configure static NAT, dynamic NAT and PAT port multiplexing and port mapping on the router to change the interface we normally access. The following is the detailed process of configuration.

First configure the host with an IP address and a gateway address.

Configure the IP address and gateway address on the virtual machine

Configure the R1 router with the port IP as the gateway address.

First log in to the web website of server 2008, which means it is interconnected and can access its web services.

The first step is to establish the configuration process of static NAT address translation. After the configuration is completed as shown in the figure, turn on ip nat debug to see the address translation process.

At this time, use the browser to refresh the website address. You can see the conversion process on the router.

You can also use the command to view NAT's address translation entries or more detailed information.

Let's delete the statically configured NAT address translation and configure the dynamic NAT address translation.

When the setup is complete and the page is refreshed again, you can see that the inside global address translated at this time is an address in the dynamic NAT translation address pool set above.

Drop the no above and add overload after it is PAT. The command does not change much, but the meaning is completely different. PAT can specify only one IP address in the address pool, but it can be used by multiple internal local addresses.

The following settings establish port multiplexing using external interface addresses.

Let's configure the NAT port mapping, which works on the server.

At this point, if you use the real machine to access the web service, you must access the following address.

The conversion process can be seen on the router as follows.

Lesson learned: static translation (static translation) translates the private IP address of the internal network into a public legal IP address. The correspondence of IP addresses is one-to-one and is constant.

Dynamic translation (dynamic translation) means that when an internal private IP is translated into a public network IP address, the correspondence of the IP is uncertain. In other words, as long as you specify which internal addresses can be translated by NAT, and which legal IP addresses can be used as external addresses, it can be translated dynamically. You can also use multiple sets of legitimate addresses.

Port multiplexing (port address translation,) PAT

Change the source IP address and source port of the outgoing packet and perform port translation, that is, port address translation adopts port multiplexing. All hosts in the internal network can share a legitimate external IP address to access the Internet. Save IP address resources to the maximum extent.

Port multiplexing uses port number translation, which is also uncertain, so it cannot be used at the same time as dynamic conversion, which can be avoided by implementing static NAT mapping.

NAT port mapping relationship: a port number that translates an internal local address in the TCP or UDP protocol into an inside global address.

On the static NAT, dynamic NAT, PAT, port mapping configuration process is shared here, I hope that the above content can have a certain reference value, you can learn to apply. If you like this article, you might as well share it for more people to see.

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