Automatic LAN/WAN port detection

• US 8,077,632 B2
• Filed: 12/12/2005
• Issued: 12/13/2011
• Est. Priority Date: 01/20/2005
• Status: Active Grant

• Current Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Original Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Inventors: Samuels, Allen R., Sutter, Paul G., Plamondon, Robert D.
• Primary Examiner(s): Ryman, Daniel J
• Assistant Examiner(s): DECKER, CASSANDRA L
• Application Number:
  US11/301,825
• Publication Number:
  US 20060159029A1
• Time in Patent Office: 2,192 Days
• Field of Search: 370/465
• US Class Current: 370/254
• CPC Class Codes: H04L 41/0809 Plug-and-play configuration
• CPC Class Codes: H04L 41/083 for increasing network speed
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies

Abstract

A system is disclosed for which a network device with two or more ports determines which of its functions should be performed on which of its ports. A method is disclosed for monitoring the traffic on each port for characteristic traffic that indicates the function that said network device should perform on said port, optionally transmitting new traffic or altering or tagging existing traffic to elicit it, and mapping said network device'"'"'s operations to its ports accordingly. Also disclosed is a system and method for auto inhibition and auto configuration.

Claims

1. An apparatus configured to automatically determine a network connection on a port, the apparatus comprising:

a first port of the apparatus located between a device on a wide area network (WAN) and a server on a local area network (LAN), the device connected to a client, the first port electrically connected to receive network traffic via the WAN, the first port comprising an Ethernet port;

a second port of the apparatus electrically connected to receive network traffic via the LAN, the second port comprising an Ethernet port, the apparatus having not yet identified to which of a network segment of the WAN or the LAN is the first port connected;

a processor of the apparatus configured to;

execute instructions to monitor network traffic on the first port and the second port to detect whether any packet received is a SYN or a SYN-ACK packet,

identify, in response to detecting that a SYN-ACK packet from the client was received from the device, that the SYN-ACK packet was received on the first port and that the first port is connected to the WAN;

automatically assign, responsive to identifying that the SYN-ACK packet was received on the first port, to the first port a function for processing communications for the network segment of the WAN connected to the first port,

forward, by the apparatus, the SYN-ACK packet from the client to the server;

identify, in response to detecting that a SYN packet was received from the server, that the SYN packet was received on the second port and that the second port is connected to the LAN;

automatically assign to the second port a function for processing communications for the network segment of the LAN connected to the second port; and

operate on subsequent packets arriving on the first port in accordance with the function assigned to the first port.

2. The apparatus of claim 1, wherein the apparatus is further configured to operate on subsequent packets arriving on the second port in accordance with the function assigned to the second port.

3. The apparatus of claim 1, wherein the apparatus is configured to operate the first port at a speed associated with the WAN and operate the second port at a speed associated with the LAN.

4. The apparatus of claim 1, wherein the apparatus removes an ACK tag from the SYN-ACK packet to create an untagged SYN packet.

5. The apparatus of claim 4, wherein the apparatus forwards the untagged SYN packet.

6. The apparatus of claim 1, wherein the apparatus tags the SYN packet with an ACK tag to create a tagged SYN-ACK packet.

7. The apparatus of claim 6, wherein the apparatus forwards the created SYN-ACK packet.

8. The apparatus of claim 1, wherein the apparatus comprises at least one from a group consisting of a router, a gateway, and a firewall.

9. The apparatus of claim 1, wherein the apparatus comprises at least one from a group consisting of a network address translator and a performance enhancing proxy.

10. The apparatus of claim 1, wherein the network traffic is Internet Protocol-based network traffic.

11. The apparatus of claim 1, wherein the SYN-ACK packet is tagged by the device.

12. The apparatus of claim 1, wherein the first and the second ports can be configured to operate on either a WAN or a LAN.

13. The apparatus of claim 1, wherein the apparatus detects the presence of the device responsive to identifying that the received SYN-ACK packet was altered.

14. A method to automatically determine, by an apparatus, a network connection on a port, the method comprising:

monitoring, by an apparatus between a gateway on a wide area network (WAN) and a server on a local area network (LAN), network traffic on a first port electrically connected to receive network traffic via the WAN, the first port comprising an Ethernet port, the gateway connected to a client;

monitoring, by the apparatus, network traffic on a second port electrically connected to receive network traffic via the LAN, the second port comprising an Ethernet port, the apparatus having not yet identified to which of a network segment of the WAN or LAN is the first port connected;

executing, by the apparatus, instructions to detect whether any packet received on the first port or the second port is a SYN or a SYN-ACK packet;

identifying, by the apparatus, in response to detecting that the SYN-ACK packet from the client was received from the gateway, that the SYN-ACK packet was received on the first port and that the first port is connected to the WAN;

automatically assigning, by the apparatus, responsive to identifying that the SYN-ACK packet was received on the first port, to the first port a function for processing communications for the network segment of the WAN connected to the first port;

forwarding, by the apparatus, the SYN-ACK packet from the client to the server;

identifying, by the apparatus, in response to detecting that a SYN packet was received from the server, that the SYN packet was received on the second port and that the second port is connected to the LAN;

automatically assigning, by the apparatus, to the second port a function for processing communications for the network segment of the LAN connected to the second port; and

operating, by the apparatus, on subsequent packets arriving on the first port in accordance with the function assigned to the first port.

15. The method of claim 14, further comprising operating on subsequent packets arriving on the second port in accordance with the function assigned to the second port.

16. The method of claim 14, further comprising operating the first port at a speed associated with the WAN and operating the second port at a speed associated with the LAN.

17. The method of claim 16, further comprising the apparatus removing an ACK tag from the SYN-ACK packet to create an untagged SYN packet.

18. The method of claim 17, further comprising the apparatus forwarding the untagged SYN packet.

19. The method of claim 14, further comprising tagging the SYN packet with an ACK tag to create a tagged SYN-ACK packet.

20. The method of claim 19, further comprising forwarding the created SYN-ACK packet.

21. The method of claim 14, wherein the apparatus comprises one of a router, a gateway or a firewall.

22. The method of claim 14, wherein the apparatus comprises a network address translator.

23. The method of claim 14, wherein the apparatus is a performance enhancing proxy.

24. The method of claim 14, further comprising:

detecting, by the apparatus, that the SYN-ACK packet from the client was modified with the ACK tag by the gateway;

removing, by the apparatus, the ACK tag from the SYN-ACK packet to create a SYN packet;

forwarding, by the apparatus, the created SYN packet to the server.