Design And Implementation Of The Translation Gateway Nat-pt And A Protocol Translation Module

IPv6 is the new generation Internet protocol designed by the IETF to replace thecurrent version of the Internet Protocol, IPv4. Most of today's networks use IPv4,but it is beginning to have problems,especialy its growing shortage of IPv4addresses. Although IPv6 solves addressing issues for customers, a long transitionperiod is likely before customers move to an exclusive IPv6 network environment.During the transition period any new IPv6-only networks will need to continue tocommunicate with existing IPv4 networks. NAT-PT is a transition mechanism to bedesigned to allow direct communication between IPv6-only networks andIPv4-only networks.The term NAT-PT stands for Network Address Translation and ProtocolTranslation. NAT refers to translation of an IPv4 address into an IPv6 address andvice-versa and PT stands for the translation of the IPv4 packet into a semanticallyequivalent IPv6 packet and vice-versa. Integrated with appropriate ALGs, NAT-PTallows native IPv6 hosts and applications to communicate with native IPv4 hostsand applications, and vice-versa,e.g. DNS and FTP.One of the benefits of NAT-PT is that no changes are required to existing hostsbecause all the NAT-PT configurations are performed at the NAT-PT gateway.Customers with existing stable IPv4 networks can setup an IPv6 network and useNAT-PT to allow communication without disrupting the existing network.This project emphasizes on the implement of essential function of NAT-PT,including network addresses transltion, protocol translation and DNS applicationlevel gateway. Some omissions of protocol translation algorithm in SIIT are verified.First of all, this article introduces some IPv6 transition mechanisms, thendescribes particularly the principle of NAT-PT and it's communication procedure.Thirdly, the article is stress on the implement of protocol translation. In this section,you can see the changes of packet from data link layer to transport layer and howIPv4-only host communicates with IPv6-only host using NAT-PT. Lastly, it analysesthe security performance of NAT-PT and proposes a mending scheme.