Network Administrator Street Smarts: A Real World Guide to CompTIA Network+® Skills, Second Edition

4.2. Task 4.2: Using the NETSTAT Utility

The Internet, and every other IP-based network for that matter, fosters communication between devices using a data structure known as a socket. Specifically, a TCP/IP socket is a 48-bit numerical value consisting of an IP address and a TCP or UDP port number. Although they're numerically identical, you can distinguish between TCP and UDP sockets by tracking the Layer 4 protocol. In essence, a socket describes a specific application running anywhere in the internetwork. The IP address leads to the device executing the application (HTTP, for example), and the Layer 4 protocol and port number uniquely lead to the specific application in question.

Microsoft operating systems and those based on UNIX use a ...