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This article will explain in detail how to understand the NAT-PT technology in the IPv6 transition technology. The content of the article is of high quality, so the editor shares it for you as a reference. I hope you will have some understanding of the relevant knowledge after reading this article.

The application of IPv6 is a gradual process. IPv4 "ocean" and IPv6 "island" will coexist and communicate with each other during the transition period. With the passage of time, IPv4 "ocean" will gradually become smaller until it will eventually be completely replaced by IPv6 "island". Before the transition is completed, the direct network communication between the two networks can be realized by NAT-PT (Network Address Translation-Protocol Translation) translation technology, that is, network address translation-protocol translation technology.

NAT-PT is an organic combination of network address translation (NAT), protocol translation (PT) and application-level gateway (ALG). It is also a way of interworking between pure IPv6 nodes and IPv4 nodes. All the translation work, including address and protocol, is done by network devices. For example, using this technology, hosts in the IPv6 network can directly access the FTP server in the IPv4 network. The following figure is a schematic diagram of address translation technology.

NAT-PT can be divided into three mechanisms to realize the conversion between IPv4 and IPv6, namely, static mapping NAT-PT mechanism, dynamic mapping NAT-PT mechanism and NAPT-PT mechanism. The static NAT-PT mechanism provides one-to-one mapping between IPv6 addresses and IPv4 addresses. The dynamic NAT-PT mechanism is a many-to-many protocol stack that takes an idle IP address from the mapping pool, and when the mapping pool IP is used up, it can no longer be mapped, that is, other IP without internal mapping cannot access the outside) and can only be accessed one-way to one side, not vice versa.

NAPT-PT (network address port translation with protocol translation) translates the ports of TCP and UDP from IPV6 to IPv4 on the basis of IP address dynamic translation. Using this "address + port number" mapping method, when different IPv6 addresses are translated, they can correspond to the same IPv4 address, and different IPv6 hosts can be distinguished by port numbers, so that multiple IPv6 hosts can share an IPv4 address to complete the translation. To put it simply, it is also called overloading, that is, many-to-one source address translation, which is an one-way access from IPv6 to IPv4, and cannot be reversed to access IPv6.

The advantage of NAT-PT is that it is simple and easy to upgrade IPv4,IPv6 nodes, but because MAT-PT has the limitations that requests and responses belonging to the same session can be converted through the same MAT-PT device, cannot convert the optional part of the IPv4 header and lacks end-to-end security, it is not recommended in some situations, so this technique is only suitable for the initial stage of the transition. With the gradual expansion of the IPv6 network, this transition technology will be replaced by newer technologies.

On how to understand the IPv6 transition technology in the NAT-PT technology to share here, I hope the above content can be of some help to you, can learn more knowledge. If you think the article is good, you can share it for more people to see.

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