What is Network Port? (Fully Explained)
A port serves as a physical docking point that allows an external device to connect to a computer. Additionally, it can function as a programmatic docking point through which data is transmitted from a program to the computer or across the Internet.
Network Port
A network port, provided by the Transport Layer protocols of the Internet Protocol suite, such as Transmission Control Protocol (TCP) and User Datagram Protocol (UDP), is a numerical identifier that facilitates endpoint communication between two computers.
Port Numbers
Different port numbers are utilized to specify which protocol incoming traffic should be directed to. These numbers enable a single host with one IP address to operate multiple network services. Each port number corresponds to a unique service, and each host can have up to 65,535 ports per IP address. The Internet Assigned Numbers Authority (IANA) oversees the management of these ports.
Categories of Ports
IANA defines three categories of ports:
1. Well-Known Ports (0 to 1023)
| Port number | Transport protocol | Service name |
|---|---|---|
| 20,21 | TCP | File Transfer Protocol |
| 23 | TCP | Telnet |
| 25 | TCP | Simple Mail Transfer Protocol(SMTP) |
| 53 | TCP and UDP | Domain Name System(DNS) |
| 110 | TCP | Post Office Protocol(POP3) |
| 123 | UDP | Network Time Protocol(NTP) |
2. Registered Ports (1024 to 49151)
Ports ranging from 1024 to 49151 are registered by IANA to specific services upon request from an entity.
3. Dynamic or Private Ports (49152 to 65535)
These ports, which span from 49,152 to 65,535, can be utilized by private or customer services or for temporary applications.
.jpg)
