| 10.2 |  | Overview of Transport Layer Ports |
| 10.2.4 |  | Port numbering and well-known port numbers |

| Port numbers are represented by 2 bytes in the header of a TCP or UDP segment. This 16-bit value can result in port numbers ranging from 0 to 65535. These port numbers are divided into three different categories: well-known ports, registered ports, and dynamic or private ports. The first 1023 ports are well-known ports. As the name implies, these ports are used for well-known network services, such as FTP, Telnet, or DNS. Registered ports range from 1024 to 49151. Ports between 49152 and 65535 are defined as dynamic or private ports.
| Interactive Media Activity Drag and Drop: Port Numbers After completing this activity, the student will be able to understand port numbers.
| Web Links Port Knowledgebase http://www.iss.net/security_center/ advice/Exploits/Ports/