Examining IP Packets: The Early DaysInitial Time to Live (IP Layer)The Don’t Fragment Flag (IP Layer)The IP ID Number (IP Layer)Type of Service (IP Layer)Nonzero Unused and Must Be Zero Fields (IP and TCP Layers)Source Port (TCP Layer)Window Size (TCP Layer)Urgent Pointer and Acknowledgment Number Values (TCP Layer)Options Order and Settings (TCP Layer)Window Scale (TCP Layer, Option)Maximum Segment Size (TCP Layer, Option)Time-Stamp Data (TCP Layer, Option)Other Passive Fingerprinting Venues