To protect all the legal income of non-labouring,first of all,we should distinguish the legal income of non-labouring from the illegal income,and figure out the reason.

In the long time, whether illegal income should be levied taxes has beena controversial issue.

Whether illegal income is taxable is regarded as important all over the world.

The paper introduces ARP protocol, the implement of ARP in Windows system, and designs the system of the detection and block on illegal connection to LAN.

Although IDS can defend viruses and illegal intrusions effectively on the internet,it has a performance bottleneck when efficiency is highly count,especially on the high-speed network.