The document describes the design and implementation of a network firewall to prevent operating system fingerprinting. Key aspects include: - The firewall uses iptables rules to drop packets attempting TCP or ICMP response analysis that could reveal the operating system. - It also implements MAC address filtering to block specific external computers deemed malicious. - Testing showed the firewall successfully prevented operating system fingerprinting via Nmap and restricted access based on MAC addresses as designed.

1. THE DESIGN AND IMPLEMENTATION OF A NETWORK FIREWALL TO PREVENT THE USE OF OPERATING SYSTEM FINGERPRINTING BY DENNIS J. CALHOUN CHARMIN GREEN PROJECT ADVISOR: DR. MOHAMMAD BODRUZZAMAN CO-ADVISOR: MR. MATTHEW MURRAY

14. Decision Matrix

16. Functional Block Diagram Pre Routing Input Forward Output Post Routing Internal network Filter Filter Filter NAT

22. 3 WAY HANDSHAKE PROCESS [10] Tony Bautts, Terry Dawson, Gregor N. Purdy. Linux Network Administration Guide 3rd Edition. Sebastopol, CA: O’Reilly Media, Inc., 2005. SYN SYN/ACK ACK Source Destination

25. Design Theory: [10] Tony Bautts, Terry Dawson, Gregor N. Purdy. Linux Network Administration Guide 3rd Edition. Sebastopol, CA: O’Reilly Media, Inc., 2005. IPTABLES NAT MANGLE FILTER INPUT OUTPUT FORWARD INPUT OUTPUT POST-ROUT PRE- ROUT OUTPUT POST- ROUT

31. Testing Environment

36. Testing and Analysis

41. Testing and Analysis

50. Questions ?????