Network security devices and methods

1. A method of providing enhanced security to a network using a network entry device, comprising:

receiving a first data packet from a host device at a first port of the network entry device, said first data packet having a source address field including a first network layer source address identifying the host device, a destination address field including a destination address identifying a destination device on the network, and a payload field including data;

replacing the first network layer source address with a private address associated with the first port on the network device so as to produce a first modified data packet; and

sending the first modified data packet to the destination device over the network, wherein nodes on the network recognize the private address as a valid address.

2. The method of claim 1 , wherein the network is a Fibre Channel network and the first network layer source address is a globally unique world wide name assigned to the host device.

3. The method of claim 1 , wherein the network is a storage area network and the first network layer source address is a globally unique world wide name assigned to the host device.

4. The method of claim 1 , wherein the network entry device is a controller card.

5. The method of claim 4 , wherein the controller card is implemented in an edge switch.

6. The method of claim 1 , wherein the host has a dedicated connection to the first port of the network entry device, the first port is one of a plurality of ports being respective entry points for packets into the network, and the private address identifies the first port of the network entry device as the entry point for the packet into the network.

7. The method of claim 6 , wherein the private address is one of a plurality of valid private addresses each associated with a respective one of the ports and identifying the respective port as an entry point into the network, and wherein the method further includes pre-informing the destination device of each of the valid private addresses to enable the destination device to identify an entry point into the network for each packet received by the destination device.

8. The method of claim 1 , wherein the packet is a first packet from the host device, and further including:

in response to receiving the first packet, creating an entry in an address table in the network entry device, said entry including the private address and the first network layer source address.

9. The method of claim 8 , further including, for subsequent packets received from the host device at the first port:

performing a lookup in the address table using the first network layer source address identifying the host device to obtain the corresponding private address; and

replacing the first network layer source address with said corresponding private address.

10. The method of claim 8 , further comprising:

receiving a reply data packet from the destination device, the reply data packet having said private address in a destination address field;

accessing the table using the private address from the reply data packet to obtain the first network layer source address from the entry;

replacing the private address in the destination address field of the reply packet with said first network layer source address obtained from the entry so as to produce a modified reply packet; and

sending the modified reply packet to the host device.

11. The method of claim 1 , wherein the network layer source address is recognized as valid by devices outside the network but the private address is not recognized as valid by the devices outside the network.

12. A network device that provides enhanced security to a network, the device comprising:

a first network entry port for receiving data packets from a host device external to the network, wherein a first data packet is received from the host device, said first data packet having a source address field including a first network layer source address identifying the host device, a destination address field including a destination address identifying a destination device on the network, and a payload field including data;

an address replacement module configured to replace network layer source addresses with private addresses, wherein the first network layer source address of the first data packet is replaced with a first private address associated with the first network entry port on the network device so as to produce a first modified data packet; and

a network port coupled to the network,

wherein the first modified data packet is sent from the network port to the destination device over the network, and wherein nodes on the network recognize the first private address as a valid address.

13. The device of claim 12 , wherein the network is a Fibre Channel network and the first network layer source address is a globally unique world wide name assigned to the host device.

14. The device of claim 12 , wherein the network is a storage area network and the first network layer source address is a globally unique world wide name assigned to the host device.

15. The device of claim 12 , wherein the device is implemented in a controller card on the edge of the network.

16. The device of claim 12 , further including a memory for storing an address table, and wherein the packet is a first packet from the host device, and the address replacement module creates an entry in the address table in response to receiving the first packet, said entry including the first private address and the first network layer source address.

17. The device of claim 16 , wherein for subsequent packets received from the host device at the first network entry port, the address replacement module performs a lookup in the address table using the first network layer source address identifying the host device to obtain the first private address, and replaces the first network layer source address with said first private address.

18. The device of claim 17 , wherein the first private address is one of a plurality of valid private addresses each associated with a respective one of the ports and identifying the respective port as an entry point into the network, and wherein the method further includes pre-informing the destination device of each of the valid private addresses to enable the destination device to identify an entry point into the network for each packet received by the destination device.

19. The device of claim 16 , wherein the device receives a reply data packet from the destination device via the network port, the reply data packet having said first private address in a destination address field, wherein the address replacement module is configured to access the address table using the first private address from the reply data packet to obtain the first network layer source address from the entry and to replace the first private address in the destination address field of the reply packet with said first network layer source address obtained from the entry so as to produce a modified reply packet, and wherein the modified reply packet is sent to the host device via the first network entry port.

20. The device of claim 12 , further including an encapsulation/decapsulation module, coupled to the address replacement module, configured to encapsulate modified data packets and decapsulate encapsulated modified reply packets.

21. The device of claim 12 , wherein the first network layer source address is recognized as valid by devices outside the network but the first private address is not recognized as valid by the devices outside the network.