Method and device for realizing NAT

Abstract

The invention discloses a method and device for realizing NAT. The method comprises the following steps: creating a mapping table and a filtering table, and correspondingly setting a first key value and a second key value for inquiring the mapping table and the filtering table; when a message is sent from a private network to a public network, realizing address NAT conversion via the mapping table; when the message is sent from the public network to the private network, realizing the address NAT conversion via the filtering table; and then forwarding the message after the NAT conversion. By adoption of the method and device disclosed by the invention, diversified demands of users can be satisfied, and the mapping table and the filtering table are simple in structures, small in internal memory space occupation and high in query efficiency. In the method and device disclosed by the invention, an address mapping relation is recorded by the mapping table, therefore the ip resource utilization rate of the public network can be improved, moreover the times of accessing an address pool in the NAT conversion process of the message can also be greatly reduced, and thus the NAT efficiency is improved.

Description

technical field [0001] The invention relates to the field of network communication, in particular to the technology for realizing NAT (Network Address Translation, network address translation). Background technique [0002] NAT was proposed in 1994 to solve the problem of exhaustion of ipv4 address resources. The basic principle of NAT is that the private network host will be assigned a legal public network address when it needs to access the public network, and the private network address will be used for internal interconnection. [0003] The private network IP address refers to the IP address of the internal network or host, and the public network IP address refers to the globally unique IP address on the Internet. NAT is the process of converting the IP address in the IP datagram header to another IP address. [0004] A typical application scenario of NAT is one-to-many NAT or many-to-many NAT. In this application scenario, multiple host port pairs (Pri_ip:port) of th...

AI Technical Summary

Problems solved by technology

[0006] The traditional method is to use NAT logs or address translation tables to indirectly implement the mapping filtering mode, but both have disadvantages

The NAT log method has the disadvantage that the system overhead increases with the increase of NAT log records

However, the address translation table cannot be flexibly configured, cannot support multiple mapping and filtering modes at the same time, and cannot meet the diverse needs of users.

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