What means NAT and how it works?

Do you think that your security in the Internet is under threat. NAT is procedure when a networking device (habitually firewall) misappropriates computer’s public address inside a internal network. The most usable purpose of NAT is to restrict count of IP addresses for safety ensuring.

One of method of network translation engages a whole internal network which uses addresses in internal diapason, where can be different addresses (from to 192.168.l.254 or from to There are a lot of variants of IP addresses for local network. Local addressing method works perfectly for PCs that only need to get network resources. In local network routers can direct traffic among local addresses without troubles. These PCs need to have publicly available address for response to requests and getting access external network. That situation when NAT is needed.


Internet requests, that are required for NAT, are comprehensive but happen so fast and common users don’t know what happen. Computer gets internet request from network workstation. Routers which are inside network accept, that request isn’t for network resource, and send it to firewall. Request is seen by firewall. Then firewall use public address to make request in the Internet. Response is returned to internal network computer from Internet. As Internet resource, this process is translating information to firewall address. Network workstation job is providing directly connection from site to the Internet. All users of internal network, which is ensured by NAT, have the same IP address. So a large number of people need only one publicly available address.

Nowadays, there are firewalls which can set up communication between network workstation and resource of the internet. They are able to observe connection details. This process was called as observing of the state of network connection. So they can observe session, which are composed of connection between workstation and firewall, between firewall and the Internet. After session ending, firewall forgets all information about this connection.

There is one more way of using NAT. The biggest networks have servers which work as web servers. It’s necessary to have Internet connection. Firewall IP addresses are specified for these servers. You can get to them only by using these addresses. Firewall is extra security layer which located in middle of external world and protected internal network. You can add ports, which would be got access, and other rules. Internal traffic can be translated more effective to the same resources and let access to more ports, while firewall access is restricted, by network specialists. Moreover, you can use it to log messages among network and the outside world.

This article told you about ways of using Network Address Translation and processes that happens inside. You can use this knowledge to make your friends amaze, to conduct lecture or else. Now, you know that NAT is one of the main aspects of Internet security.