Terminology Index
Glossary
2953 terms
Ports
Numbered endpoints on a host that identify specific services or processes for network communication. Together with IP addresses, ports tell traffic where to go, and they are a primary attack surface.
Ports are 16-bit identifiers used at the transport layer (TCP and UDP) to distinguish services running on a host: web servers on 80/443, SSH on 22, databases on their own ports. An open port means a service is listening; that service can be reached, and potentially attacked. Defenders inventory open ports, close unneeded ones, and limit access to those that must stay open. Understanding ports is foundational networking and to reasoning about exposure and attack surface.
Introduced in: Networking Foundations
Examples
- A web server listening on port 443 for HTTPS connections.
- Recognizing SSH typically on port 22 and databases on dedicated ports.
- Closing unneeded open ports to shrink attack surface.
