Solution to the problem of illegal use of LAN IP address

Introduction

In most local area network operation management work, the network administrator is responsible for managing the User IP address assignment, after the user registers correctly is considered the legitimate user. Any user who uses an unauthorized IP address on a local area network should be considered an illegal use of IP.

However, in the Windows operating system, the end user can freely modify the IP address settings, resulting in the illegal use of IP address problems. The following changes may occur when the changed IP address is running on the LAN. 

A. An illegal IP address, or IP address, is not within the scope of a planned LAN.

B. Duplicate IP addresses have resource conflicts with legitimate IP addresses that are already allocated and running on the LAN, making it impossible for legitimate users to access the Internet.

C. To use the IP address of a legitimate user when the legal user is not in line, use its IP address to network, so that the rights and interests of legitimate users are infringed.

1.IP the motive of illegal use of address

The problem of illegal use of IP address is not a common technical problem, but a management problem. Only by finding out the reason for its existence, and eradicating its existence, can it fundamentally prevent its occurrence. An analysis of the motives of illegal users is as follows:

A. Disrupt and disrupt the normal operation of network servers and network devices.

B. The privilege of attempting to possess an IP address that has been illegally used. The most typical is the Internet access rights.

C. Inadvertent illegal use due to machine reinstallation, temporary deployment and other reasons.

2. Methods of illegal use

2.1 Statically modified IP address configuration when the user configures TCP/IP options, it uses an IP address that is not assigned by the administrator, which forms the illegal use of the IP address.

2.2 Modify MAC address and IP address at the same time

It is also possible for an illegal user to change the IP address and MAC address of a computer to another legitimate host's IP address and MAC address. They can use a NIC that allows a custom MAC address or use software to modify the MAC address.

2.3IP Electronic Deception

IP spoofing is the technology that forges the IP address of a host computer. It usually needs to be programmed to implement. To send an IP packet with a fake source IP address by using socket programming