Method for detecting failure of internal server group members and network address translation device

Abstract

The invention discloses a method for detecting invalidation of group members of an internal server and network address translation (NAT) equipment. The method comprises the following steps of: if the NAT equipment receives an ICMP (Internet Control Message Protocol) target non-accessible message sent by internal network equipment, determining a non-accessible server according to the message, switching the state of the server to detection, detecting whether the server is accessible on three layers, and if not, switching the state of the server to invalid; otherwise, switching the state of the server to stale, marking a session corresponding to service flow distributed to the server with an S, switching the state of the server to delay, setting a first timer for the server, switching the state of the server to valid if the session with the mark S is switched from open state to ready state or three times of handshake of a TCP (Transmission Control Protocol) specific to the session with the mark S are successful; and otherwise, switching the state of the server to invalid. Due to the adoption of the method and the equipment, the invalidation of group members of the internal server can be detected.

Description

technical field [0001] The invention relates to the technical field of communication detection, in particular to a method for detecting failure of members of an internal server group and a Network Address Translation (NAT, Network Address Translation) device. Background technique [0002] Through the multiple servers in the NAT internal server group to jointly provide a certain service, the load sharing of internal servers can be realized. The basic principle is that the NAT device announces a virtual IP address to the outside world. When a customer accesses the virtual IP address, the NAT device maps it to a member of the internal server group through a certain hash (HASH) algorithm. [0003] figure 1 An example network diagram of an existing internal server group providing a certain service to the outside is given, such as figure 1 As shown, when a personal computer (PC, Personal Computer) 1 accesses the virtual IP address 212.1.1.2 announced by the NAT device, it may be...

AI Technical Summary

Problems solved by technology

[0005] The problem with this method is: if a member of the internal server group fails, that is, when the corresponding service cannot be provided, the NAT device cannot perceive it, and will still share part of the access to the member, resulting in these accesses not being served. Even if other valid server group members exist at this time

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