Method and device for realizing source address conversion by using address pool

Abstract

The invention discloses a method and a device for realizing source address conversion by using an address pool. The method comprises the following steps: for a message for an internal network to visit an external network, if the flow structure being matched the message does not contain NAT information, seeking the flow structure of which the internal network source address is the same as that of the message in the flow structure recorded with the NAT information, and converting the source address of the message by using the address of the address pool in the NAT information of the flow structure as the source address after conversion; and for the flow structure carrying out the source address NAT for the first time, recording the conversion relation between the source address of the internal network and the address of the address pool in the flow structure as NAT information. The invention ensures that the same internal network source address can use the same address of the address pool after NAT, thereby avoiding access failure caused by different addresses.

Description

technical field [0001] The present invention relates to the network field, in particular to a method and device for implementing source address translation by using an address pool. Background technique [0002] NAT (Network Address Translation, Network Address Translation) technology is currently widely used in IPv4 networks to solve the problem of increasing shortage of IP addresses. At the same time, the use of NAT technology can also hide the internal network and increase network security. [0003] NAT technology includes source address translation, destination address translation and static mapping. As the name implies, source address translation is an address translation based on the source address; destination address translation is an address translation based on the destination address; and static mapping is an address translation that establishes a one-to-one mapping between address A and address B. Among them, source address translation is currently the most wide...

AI Technical Summary

Problems solved by technology

[0007] When multiple addresses are included in the address pool, the current NAT implementations use address rotation (sequential selection) or random selection to select the address pool address to use. Although this can ensure the average address usage, the inventors found that in the use There will be major shortcomings in the process

For example, consider such a situation: an intranet host accesses a server on the public network that requires authentication, and access to services is allowed only after the authentication is passed. The data flow is allocated with the public network address 2, so because the source address of the authentication data flow and the converted data flow for subsequent business access are different, the data access is likely to be rejected by the server

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