Complete Guide to Default List and Types of Port Numbers – Managed by IANA

Port numbers are defined in the range of 0 ~ 65535 and are broadly divided into three categories.

List of major port numbers

1. Wellknown Port (0 – 1023)

2. Registered Port (1024 – 49151)

3. Dynamic Ports (49152 – 65535)

• Mainly used for temporary client connections (automatically assigned by OS)
• Used by web browsers and applications to access a server
• Example:
  • When a https://example.com client connects49152 to , it uses a port from below

Services where changing the default port is common

1. SSH (Default: 22)

• Recommended: As a security measure, change to a different port (for example, 2222)

sudo nano /etc/ssh/sshd_config

Modified: yaml

Port 2222

Apply:

sudo systemctl restart sshd

2. HTTP/HTTPS（80, 443）

• Enterprises and development environments often use 8080 and 8443
• For example: Nginx or Apache to 8080

How to find out the port number

1. Check the port you are using (Linux / Mac)

netstat -tulnp

or

ss -tulnp

Search for a specific port

netstat -tulnp | grep 8080

2. Check the port in Windows

netstat -ano

Or search for a specific port:

netstat -ano | findstr :8080

3. Check Docker’s public port

docker ps

Example: PORTS value

0.0.0.0:5001->5000/tcp

This indicates that the container’s 5000 port number is mapped to the host’s 5001 .

IANA（Internet Assigned Numbers Authority）

IANA (Internet Assigned Numbers Authority) is an international organization that manages the allocation of IP addresses, domain names, port numbers, protocol numbers, and more used on the internet.

IANA is the organization that manages the core identifiers of the Internet and is responsible for three main areas:

Summary

Commonly used ports:

• Web Server: 80 (HTTP), 443 (HTTPS), 8080 (代替 HTTP)
• Database: 3306 (MySQL), 5432 (PostgreSQL), 6379 (Redis)
• Remote Connection: 22 (SSH), 3389 (RDP), 5900 (VNC)

References

Internet Assigned Numbers Authority (IANA): The organization that manages the official assignment of port numbers

• IANA Service Name and Transport Protocol Port Number Registry
  • URL: https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml

RFC (Request for Comments): Standardized document

• RFC 1700: Assigned Numbers
  • URL: https://datatracker.ietf.org/doc/html/rfc1700
• RFC 6335: Internet Assigned Numbers Authority (IANA) Procedures for the Management of Service Names and Transport Protocol Port Numbers
  • URL: https://datatracker.ietf.org/doc/html/rfc6335

Example official document

• SSH (Port Number: 22)
  • SSH Communications Security
    • URL: https://www.ssh.com/
  • OpenSSH official documentation
    • URL: https://www.openssh.com/manual.html
• HTTP/HTTPS (port numbers: 80, 443)
  • RFC 2818: HTTP Over TLS
    • URL: https://datatracker.ietf.org/doc/html/rfc2818
  • Apache HTTP Server Official Documentation
    • URL: https://httpd.apache.org/docs/
  • Nginx official documentation
    • URL: https://nginx.org/en/docs/
• MySQL (port number: 3306)
  • MySQL official documentation
    • URL: https://dev.mysql.com/doc/
• PostgreSQL (port number: 5432)
  • PostgreSQL official documentation
    • URL: https://www.postgresql.org/docs/