From the course: Hardening and Secure Configuration: Ports, Baselines, Benchmarks, and Security Scoring
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Understanding ports and services
From the course: Hardening and Secure Configuration: Ports, Baselines, Benchmarks, and Security Scoring
Understanding ports and services
Think of a massive apartment building. Each door has a number. Behind some doors, there is a tenant ready to do business. Kind of a dentist, a lawyer or a tutor. Behind others, the apartment is empty. Now imagine a visitor walking down the hallway, knocking on every door. That visitor is an attacker performing a port scan. The apartment numbers are your ports. The tenants are your services. The language they speak, that is your protocol. Understanding this relationship is foundational to network hardening. And in this lecture, we'll go through the fundamental relationship between ports, services, and protocols. So let's start with the port. A port is simply a logical endpoint, not a physical hole. When you say port number 443, we are not talking about a physical jack. A port is a 16-bit number, which ranges from 0 to 65,535 that the operating system uses to direct network traffic to the correct application. When a packet arrives, the OS looks at the destination ports and asks which…
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