Understanding Network Reconnaissance Using IP Options

The Internet Protocol standard RFC 791, Internet Protocol, specifies a set of options to provide special routing controls, diagnostic tools, and security.

RFC 791 states that these options are “ unnecessary for the most common communications” and, in reality, they rarely appear in IP packet headers. These options appear after the destination address in an IP packet header, as shown in Figure 30. When they do appear, they are frequently being put to some illegitimate use.

Figure 30: Routing Options

This topic covers:

• Uses for IP Packet Header Options
• SCREEN Options for Detecting IP Options Used For Reconnaissance
• Related Topics