Router for preventing port scans and method utilizing the same

1. 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.

2. The method according to claim 1 , further comprising:

transferring the response datagram to the remote computer if the response datagram is not the ICMP port unreachable datagram.

3. The method according to claim 1 , further comprising:

dropping the ICMP port unreachable datagram if the ICMP port unreachable datagram is normal.

4. The method according to claim 1 , further comprising:

displaying the recorded port scan event on a display of the local computer.

5. The method according to claim 1 , wherein the response datagram is determined to be the ICMP port unreachable datagram if an ICMP type of the datagram is 3 and an ICMP code of the datagram is 3.

6. The method according to claim 1 , wherein the local computer is a local area network (LAN) server or a LAN station.

7. A router, the router being connected with a local computer, the local computer comprising a user datagram protocol (UDP) port, the router comprising:

a storage;

a log system to record connection logs of the local computer;

at least one processor; and

one or more programs stored in the storage and being executable by the at least one processor, the one or more programs comprising:

a transferring module operable to receive a datagram from a remote computer, and transfer the datagram to the local computer;

a receiving module operable to receive a response datagram from the local computer;

a determining module operable to determine if the response datagram is an Internet Control Messages Protocol (ICMP) port unreachable datagram according to a datagram format of the response datagram, and determine whether 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

a protection module operable to drop the ICMP port unreachable datagram if the ICMP port unreachable datagram is abnormal, and record a port scan event of the remote computer into the log system.

8. The router according to claim 7 , wherein the transferring module is further operable to transferring the response datagram to the remote computer if the response datagram is not the ICMP port unreachable datagram.

9. The router according to claim 7 , wherein the protection module is further operable to drop the ICMP port unreachable datagram if the ICMP port unreachable datagram is normal.

10. The router according to claim 7 , wherein the protection module is further operable to display the recorded port scan event on a display of the local computer.

11. The router according to claim 7 , wherein the response datagram is determined to be the ICMP port unreachable datagram if an ICMP type of the datagram is 3 and an ICMP code of the datagram is 3.

12. The router according to claim 7 , wherein the local computer is a local area network (LAN) server or a LAN station.

13. A non-transitory storage medium storing a set of instructions, the set of instructions capable of being executed by a processor to perform 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.

14. The non-transitory storage medium as claimed in claim 13 , wherein the method further comprises:

transferring the response datagram to the remote computer if the response datagram is not the ICMP port unreachable datagram.

15. The non-transitory storage medium as claimed in claim 13 , wherein the method further comprises:

dropping the ICMP port unreachable datagram if the ICMP port unreachable datagram is normal.

16. The non-transitory storage medium as claimed in claim 13 , wherein the method further comprises:

displaying the recorded port scan event on a display of the local computer.

17. The non-transitory storage medium as claimed in claim 13 , wherein the response datagram is determined to be the ICMP port unreachable datagram if an ICMP type of the datagram is 3 and an ICMP code of the datagram is 3.

18. The non-transitory storage medium as claimed in claim 13 , wherein the local computer is a local area network (LAN) server or a LAN station.