Tracing an access point in a wireless network

• US 20060209700A1
• Filed: 03/09/2006
• Published: 09/21/2006
• Est. Priority Date: 03/11/2005
• Status: Active Grant

• Current Assignee: NetScout Systems Incorporated
• Original Assignee: Airmagnet (NetScout Systems Incorporated)
• Inventors: Sundar, Jagane D., Kuan, Chia-Chee, Wu, Miles
• Granted Patent: US 8,437,263 B2
• Time in Patent Office: Days
• US Class Current: 370/248
• CPC Class Codes: H04L 63/10 for controlling access to devices or network resources
• CPC Class Codes: H04L 63/1441 Countermeasures against malicious traffic countermeasures against attacks on cryptographic mechanisms H04L9/002
• CPC Class Codes: H04W 12/088 using filters or firewalls
• CPC Class Codes: H04W 12/122 Counter-measures against attacks; Protection against rogue devices
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

An access point in a wireless network is traced by sending an internet protocol (IP) packet from a detector to the access point through the wireless network. The detector and the access point are connected through a private wired network. The IP packet is sent with the source IP address field and the destination IP address of the IP packet set to the wireless IP address and wired IP address, respectively, of the detector. The IP packet is routed back to the detector through a switch in the private wired network. When the IP packet is received at the detector, a source IP address, which corresponds to the port on the switch used to send the IP packet, is determined from the received IP packet.

Claims

1. A method of tracing an access point in a wireless network, the method comprising:

setting a source internet protocol (IP) address field of an IP packet to a wireless IP address of a detector associated with the access point through the wireless network, wherein the detector and the access point are connected through a private wired network;

setting a destination IP address field of the IP packet to a wired IP address of the detector;

sending the IP packet from the detector to the access point through the wireless network,

routing the IP packet from the access point back to the detector through a switch in the private wired network;

receiving the routed IP packet at the detector; and

determining a source IP address from the received IP packet, wherein the source IP address corresponds to a port on the switch used to route the IP packet back to the detector.

2. The method of claim 1, wherein the access point is connected to the port on the switch without being connected through another switch, and further comprising:

identifying the port on the switch to which the access point is connected using the source IP address determined from the received IP packet.

3. The method of claim 2, wherein routing the IP packet further comprises:

relaying the IP packet through a set of one or more switches in the private wired network.

4. The method of claim 3, further comprising:

tracing through the set of one or more switches to identify the port on the switch to which the access point is connected using the source IP address determined from the received IP packet.

5. The method of claim 4, wherein one of the set of one or more switches is a last-hop switch, which sends the IP packet to the detector without relaying the IP packet through another switch, and wherein tracing through the set of one or more switches comprises:

identifying a port on the last-hop switch that was used to send the IP packet to the detector using the source IP address;

determining if the port on the last-hop switch is connected to another switch; and

if the port is connected to another switch;

a) identifying a port on that switch;

b) determining if the port identified in a) is connected to yet another switch; and

c) repeating a) and b) until a port is identified that is not connected to another switch, wherein the port that is not connected to another switch is the port on the switch that is connected to the access point.

6. The method of claim 1, further comprising:

before the IP packet is sent from the detector to the access point through the wireless network, copying the wireless IP address of the detector into a data field of the IP packet; and

when the IP packet is received at the detector, comparing the source IP address field of the IP packet to the wireless IP address in the data field of the IP packet,

wherein if the source IP address field and the wireless IP address are the same, the IP packet was not network address translated, and

wherein if the source IP address field and the wireless IP address are not the same, the IP packet was network address translated.

7. A method of tracing an access point in a wireless network, the method comprising:

setting a source internet protocol (IP) address field of an IP packet to a wireless IP address of a detector associated with the access point through the wireless network, wherein the detector and the access point are connected through a private wired network;

setting a destination IP address field of the IP packet to a wired IP address of the detector;

sending the IP packet from the detector to the access point through the wireless network, wherein the IP packet is routed from the access point back to the detector through a switch in the wired network;

receiving the IP packet at the detector; and

determining a source IP address from the received IP packet, wherein the source IP address corresponds to a port on the switch used to route the IP packet back to the detector.

8. The method of claim 7, wherein determining a source IP address comprises:

examining the source IP address field of the IP packet received at the detector to obtain the source IP address.

9. The method of claim 7, wherein the access point is connected to the port on the switch without being connected through another switch, and further comprising:

identifying the port on the switch to which the access point is connected using the source IP address determined from the received IP packet.

10. The method of claim 9, wherein the IP packet is relayed through a set of one or more switches.

11. The method of claim 10, further comprising:

tracing through the set of one or more switches to identify the port on the switch to which the access point is connected using the source IP address determined from the received IP packet.

12. The method of claim 11, wherein one of the set of one or more switches is a last-hop switch, which sends the IP packet to the detector without relaying the IP packet through another switch, and wherein tracing through the set of one or more switches comprises:

identifying a port on the last-hop switch that was used to send the IP packet to the detector using the source IP address;

determining if the port on the last-hop switch is connected to another switch; and

if the port is connected to another switch;

a) identifying a port on that switch;

b) determining if the port identified in a) is connected to yet another switch; and

c) repeating a) and b) until a port is identified that is not connected to another switch, wherein the port that is not connected to another switch is the port on the switch that is connected to the access point.

13. The method of claim 7, further comprising:

before the IP packet is sent from the detector to the access point through the wireless network, copying the wireless IP address of the detector into a data field of the IP packet; and

when the IP packet is received at the detector, comparing the source IP address field of the IP packet to the wireless IP address in the data field of the IP packet,

wherein if the source IP address field and the wireless IP address are the same, the IP packet was not network address translated, and

wherein if the source IP address field and the wireless IP address are not the same, the IP packet was network address translated.

14. A system to trace an access point in a wireless network, the system comprising:

a detector associated with the access point through the wireless network, wherein the detector and the access point are connected through a private wired network,

wherein the detector has a wireless internet protocol (IP) address and a wired IP address,

wherein the detector is configured to send an IP packet to the access point,

wherein a source IP address field of the IP packet is set to the wireless IP address of the detector,

wherein a destination IP address field of the IP packet is set to the wired IP address of the detector,

wherein the IP packet is routed from the access point back to the detector through a switch in the private wired network, and

wherein, when the IP packet is received at the detector, a source IP address used by the switch to send the IP packet to the detector through the private wired network is determined.

15. The system of claim 14, further comprising:

a terminal connected to the detector, wherein the terminal is configured to;

determine the source IP addressed from the IP packet received at the detector; and

identify a port on the switch to which the access point is connected using the source IP address determined from the received IP packet.

16. The system of claim 15, whereon the switch comprises:

a set of one or more switches, wherein the IP packet is relayed through the set of one or more switches.

17. The system of claim 16, wherein the terminal is further configured to:

trace through the set of one or more switches to identify the port on the switch to which the access point is connected using the source IP address determined from the received IP packet.

18. The system of claim 17, wherein one of the set of one or more switches is a last-hop switch that sends the IP packet to the detector without being relayed through another switch, and wherein the terminal is configured to trace through the set of one or more switches by:

identifying a port on the last-hop switch that was used to send the IP packet to the detector using the source IP address;

determining if the port on the last-hop switch is connected to another switch; and

if the port is connected to another switch;

a) identifying a port on that switch;

b) determining if the port identified in a) is connected to yet another switch; and

c) repeating a) and b) until a port is identified that is not connected to another switch, wherein the port that is not connected to another switch is the port on the switch that is connected to the access point.

19. The system of claim 14, wherein the terminal is further configured to:

before the IP packet is sent from the detector to the access point through the wireless network, copy the wireless IP address of the detector into a data field of the IP packet; and

when the IP packet is received at the detector, compare the source IP address field of the IP packet to the wireless IP address in the data field of the IP packet,

wherein if the source IP address field and the wireless IP address are the same, the IP packet was not network address translated, and

wherein if the source IP address field and the wireless IP address are not the same, the IP packet was network address translated.

20. A computer-readable storage medium containing computer executable instructions to trace an access point in a wireless network, comprising instructions for:

setting a source internet protocol (IP) address field of an IP packet to a wireless IP address of a detector associated with the access point through the wireless network, wherein the detector and the access point are connected through a private wired network;

setting a destination IP address field of the IP packet to a wired IP address of the detector;

sending the IP packet from the detector to the access point through the wireless network,

routing the IP packet from the access point back to the detector through a switch in the private wired network;

receiving the routed IP packet at the detector; and

determining a source IP address from the received IP packet, wherein the source IP address corresponds to a port on the switch used to route the IP packet back to the detector.

21. A method of tracing an access point in a wireless network, the method comprising:

a) locating access points in the wireless network using a detector, wherein the detector is connected to a private wired network;

b) identifying unauthorized access points among any access points located in a);

c) sending an internet protocol (IP) packet to an access point identified as an unauthorized access point in b) through the wireless network,

wherein a source IP address field of the IP packet is set to a wireless IP address of the detector, and

wherein a destination IP address field of the IP packet is set to a wired IP address of the detector;

d) if the IP packet is not returned to the detector through the private wired network connected to the detector, determining that the access point to which the IP packet was sent is not connected to the same private wired network as the detector; and

e) if the IP packet is returned to the detector through the private wired network connected to the detector, determining that the access point to which the IP packet was sent is connected to the same private wired network as the detector.

22. The method of claim 21, further comprising:

if multiple access points are identified in b) as being unauthorized access points, performing c)-e) for each of the access points identified as being unauthorized access points.

23. The method of claim 21, wherein the detector is connected to a switch in the private wired network, and further comprising:

when the IP packet is returned to the detector through the private wired network in e), identifying a port on the switch used to send the IP packet to the detector.

24. The method of claim 23, further comprising:

determining a source IP address from the IP packet returned to the detector, wherein the port on the switch is identified using the determined source IP address.

25. The method of claim 21, further comprising:

when the IP packet is returned to the detector through the private wired network in e), determining if the IP packet was network address translated.

26. The method of claim 25, further comprising:

before sending the IP packet in c), copying the wireless IP address of the detector into a data field of the IP packet; and

when the IP packet is returned to the detector through the private wired network in e), determining a source IP address from the IP packet returned to the detector and comparing the source IP address determined from the returned IP packet to the wireless IP address in the data field of the returned IP packet,

wherein if the source IP address determined from the returned IP packet and the wireless IP address in the data field of the returned IP packet are different, the IP packet was network address translated.

27. A system to trace an access point in a wireless network, the system comprising:

a detector located in the wireless network, wherein the detector is connected to a private wired network,

wherein the detector is used to locate access points in the wireless network,

wherein unauthorized access points are identified among any access points located in the wireless network,

wherein the detector is used to send an internet protocol (IP) packet to an access point identified as an unauthorized access point through the wireless network,

wherein a source IP address field of the IP packet is set to a wireless IP address of the detector,

wherein a destination IP address field of the IP packet is set to a wired IP address of the detector,

wherein if the IP packet is not returned to the detector through the private wired network connected to the detector, the access point to which the IP packet was sent is determined to be not connected to the same private wired network as the detector, and

wherein if the IP packet is returned to the detector through the private wired network connected to the detector, the access point to which the IP packet was sent is determined to be connected to the same private wired network as the detector.

28. The system of claim 27, wherein the detector is connected to a switch in the private wired network, and wherein, when the IP packet is returned to the detector through the private wired network, a port on the switch used to send the IP packet to the detector is identified.

29. The system of claim 28, wherein a source IP address is determined from the IP packet returned to the detector, and wherein the port on the switch is identified using the determined source IP address.

30. The system of claim 27, wherein, before the IP packet is sent, the wireless IP address of the detector is coped into a data field of the IP packet, wherein, when the IP packet is returned to the detector through the private wired network, a source IP address is determined from the IP packet returned to the detector and compared to the wireless IP address in the data field of the returned IP packet, and wherein if the source IP address determined from the returned IP packet and the wireless IP address in the data field of the returned IP packet are different, the IP packet was network address translated.

31. A computer-readable storage medium containing computer executable instructions to trace an access point in a wireless network, comprising instructions for:

a) locating access points in the wireless network using a detector, wherein the detector is connected to a private wired network;

b) identifying unauthorized access points among any access points located in a);

c) sending an internet protocol (IP) packet to an access point identified as an unauthorized access point in b) through the wireless network,

wherein a source IP address field of the IP packet is set to a wireless IP address of the detector, and

wherein a destination IP address field of the IP packet is set to a wired IP address of the detector;

d) if the IP packet is not returned to the detector through the private wired network connected to the detector, determining that the access point to which the IP packet was sent is not connected to the same private wired network as the detector; and

e) if the IP packet is returned to the detector through the private wired network connected to the detector, determining that the access point to which the IP packet was sent is connected to the same private wired network as the detector.