Overview
While an IP address identifies a device, a port number identifies a specific application or service running on that device. Ports range from 0 to 65535.
Port Ranges
- Well-Known Ports (0-1023): Reserved for standard services (e.g., HTTP: 80, HTTPS: 443, FTP: 21).
- Registered Ports (1024-49151): Assigned by IANA for specific applications.
- Dynamic/Private Ports (49152-65535): Used for temporary client-side connections.
Role in Transport Layer
TCP and UDP use port numbers to multiplex multiple communication streams over a single IP address.