Author: Insist--
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foreword
With the continuous development of the network, there are more and more network applications, and the limited IPV4 addresses are not enough. Therefore, NAT technology has emerged. This article will talk about NAT technology.
Table of contents
Second, the implementation of NAT
1. Save public legal IP addresses
2. Dealing with address overlap
2. The complexity of configuration and maintenance
3. Some applications are not supported, which can be avoided by static NAT mapping
1. What is NAT technology?
NAT (full name: Network Address Translation), Chinese means "network address translation". It is an address conversion technology , which can convert the IP address in the header of the IP data packet into another IP address, and achieve the purpose of address reuse by converting the port number. In layman's terms, it means that all computers in the company can be used under one public IP address, which can solve the problem of insufficient local public IP addresses to a certain extent.
Second, the implementation of NAT
1. Static NAT
The implementation of this technology is to map a single internal IP address with a single external IP address, thereby realizing the interconnection between the internal network and the external network. Its entire mapping list is fixed. Because this mapping is fixed , it will not change as the network changes.
2. Dynamic NAT
The difference between dynamic NAT technology and static NAT technology is that its mapping is dynamic and can be adjusted according to the needs of the internal network, so as to ensure the communication between the internal network and the external network.
3. Port multiplexing (PAT)
The PAT technology is based on the dynamic mapping technology and realizes the interconnection between the internal network and the external network through port number mapping. In this way, the internal private IP address can correspond to the external public IP address, and can be identified through different port numbers, so as to realize the function of network communication.
Three, the advantages of NAT
1. Save public legal IP addresses
2. Dealing with address overlap
3. Enhance flexibility
4. Security
4. Disadvantages of NAT
1. Increased delay
2. The complexity of configuration and maintenance
3. Some applications are not supported, which can be avoided by static NAT mapping
Five, the role of NAT
NAT can enable computers in the intranet to access the public network through a public IP address, thus realizing the function of sharing one IP address for multiple intranet computers. NAT can also filter and block some unallowed network connections, thereby enhancing network security.