Intelligent firewall

1. A method of preventing unauthorized access to a system, comprising:

receiving a data packet at a firewall, the data packet comprising an ethernet frame field and a source address, wherein the firewall does not use a communication address;

analyzing the data packet with the firewall to determine the final disposition of the data packet; and

handling the data packet according to its final disposition, wherein handling the data packet comprises determining whether to drop the data packet or send the data packet to a final destination, and handling the data packet further comprises dropping the data packet or sending the data packet to the final destination using the ethernet frame field, the data packet sent without changing the ethernet frame field or the source address, wherein the firewall adds information for security analysis to the data packet without violating a network communication protocol.

2. The method of claim 1 , wherein the added information is an IP address from the originating source of the data packet.

3. The method of claim 1 , wherein the added information is the operating system used by the data packet.

4. The method of claim 1 , wherein the added information is a compression flag.

5. The method of claim 1 , wherein the added information is a window size flag.

6. The method of claim 1 , wherein the added information is state session information.

7. The method of claim 1 , wherein the added information is communication port information.

8. The method of claim 1 , wherein the system is a network.

9. The method of claim 1 , wherein the data packet is analyzed by a pattern matching system.

10. The method of claim 1 , further comprising: replacing padded data from the data packet, where the padded data is required by as system protocol.

11. The method of claim 10 , wherein the padded data is added to meet a minimum size requirement of the system protocol.