Patent ID: 8261349

Claim:
A method for preventing port scans using a router, the router being connected with a local computer, the router providing a log system to record connection logs of the local computer, the local computer comprising a user datagram protocol (UDP) port, the method comprising: receiving a datagram from a remote computer by the router, and transferring the datagram to the local computer; receiving a response datagram from the local computer; determining if the response datagram is an Internet Control Messages Protocol (ICMP) port unreachable datagram according to a datagram format of the response datagram; determining if the ICMP port unreachable datagram is normal according to connection logs between the local computer with the remote computer using the log system, if the response datagram is the ICMP port unreachable datagram; and dropping the ICMP port unreachable datagram if the ICMP port unreachable datagram is abnormal, and recording a port scan event of the remote computer into the log system.