Method for solving port scanning and attack rejection in NAT environment

A port scanning and environmental technology, applied in the direction of data exchange through path configuration, digital transmission system, electrical components, etc., can solve the problem that other hosts cannot forward packets normally, so as to prevent port scanning and reject attacks, and mitigate attacks Effect

Inactive Publication Date: 2008-08-27
上海艾泰科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problem that the present invention needs to solve is to provide a kind of method that solves port scan and denial attack under NAT environment, aims to solve the attack (such as port scan and denial attack etc.) Defects of Normal Packet Forwarding

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] Setting: Cmin(n)=200, Cmax(n)=800, Pmax(n)=0.2, for a connection request, if the current connection number is less than 200, the router allows the connection to be established, if the current connection number has exceeded 800, the router rejects the connection request. If the current number of connections is 201, perform the following steps:

[0043] Suppose count(n)=1;

[0044] Pb(n)=0.2*(201-200) / (800-200)=0.00033;

[0045] Pa(n)=0.00033 / (1-1*0.00033)=0.00033;

[0046] Therefore, the router rejects the 201st connection with a probability of 0.00033; or, allows the connection of the host N to be established with a probability of 1-0.00033.

Embodiment 2

[0048] Setting: Cmin(n)=200, Cmax(n)=800, Pmax(n)=0.2, for a connection request, if the current connection number is less than 200, the router allows the connection to be established, if the current connection number has exceeded 800, the router rejects the connection request. If the current number of connections is 751, perform the following steps:

[0049] Suppose count(n)=10;

[0050] Pb(n)=0.2*(751-200) / (800-200)=0.184;

[0051] Pa(n)=0.184 / (1-10*0.184)=0.22;

[0052] Therefore, the router rejects the 751st connection with a probability of 0.22; or, allows the connection of the host N to be established with a probability of 1-0.22.

[0053] It can be seen from the above examples: if the current number of connections is between the minimum value and the maximum value, it tells us that the behavior of the host is in a critical state. In this state, a probability Pa(n) needs to be calculated, and then the router uses this probability Pa (n) Establish or deny the host's re...

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PUM

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Abstract

This invention refers to a method for terminal scanning and stopping attack, which contains initializing NAPT list, setting a minimum value of permitted connection number for main frame connecting with router, setting the maximum value of permitted connection number for main frame connecting with router, if the value is less than the minimum the router requesting connection, if the value is greater than the maximum the refusing the connection request, if the value is greater than or equal to minimum or less than or equal to maximum the router setting or refusing request of main frame by probability. Said invention can satisfy current NAY flow and reduce DDOS attack.

Description

technical field [0001] The invention relates to a method for solving port scanning and rejecting attacks in a router, in particular to a method for solving port scanning and rejecting attacks in a NAT environment. Background technique [0002] As we all know, due to the shortage of IPv4 address space, IEFT proposes to adopt IP NAT (IPNetwork Address Translation, RFC2663) to solve the problem of insufficient number of IP addresses. [0003] But in the NAT environment, the router uses a NAPT (Network Address Port Translation) table to record the information of NAT packet translation. This NAPT table contains the host's source IP address (Source IP Address), source port number (Source Port Number) , the destination IP address (Destination IP Address), the destination port number (Destination Port Number), the protocol number (Protocol ID) and the converted address (Global IP Address), etc.; due to NAT conversion, a converted address is theoretically only 65536 ports, and the I...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L12/28H04L12/24
Inventor 张洪忠
Owner 上海艾泰科技有限公司
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