Port > Well Known Ports

Well-known ports are network port numbers that are reserved for specific, widely-recognized services and protocols. These ports are standardized by the Internet Assigned Numbers Authority (IANA) to ensure consistency in network communication. Here are some common well-known ports and the services or protocols they are associated with:

Well-Known Ports (0-1023):

1. Port 21 – FTP (File Transfer Protocol): Used for file transfer.
2. Port 22 – SSH (Secure Shell): Secure remote access.
3. Port 23 – Telnet: Remote command-line access.
4. Port 25 – SMTP (Simple Mail Transfer Protocol): Used for sending email.
5. Port 53 – DNS (Domain Name System): Used for domain name resolution.
6. Port 67/68 – DHCP (Dynamic Host Configuration Protocol): IP address allocation.
7. Port 69 – TFTP (Trivial File Transfer Protocol): Simple file transfer.
8. Port 80 – HTTP (Hypertext Transfer Protocol): Standard web browsing.
9. Port 110 – POP3 (Post Office Protocol version 3): Used for email retrieval.
10. Port 123 – NTP (Network Time Protocol): Time synchronization.
11. Port 135 – MS RPC (Microsoft Remote Procedure Call): Communication in Windows.
12. Port 137-139 – NetBIOS: Communication between Windows machines.
13. Port 143 – IMAP (Internet Message Access Protocol): Email retrieval.
14. Port 161 – SNMP (Simple Network Management Protocol): Network management.
15. Port 194 – IRC (Internet Relay Chat): Chat communication.
16. Port 443 – HTTPS (HTTP over SSL/TLS): Secure web browsing.
17. Port 445 – SMB (Server Message Block): File and printer sharing in Windows.
18. Port 465/587 – SMTP over SSL/TLS: Secure email transmission.
19. Port 514 – Syslog: System log messages.
20. Port 636 – LDAPS (Lightweight Directory Access Protocol over SSL/TLS): Secure LDAP communication.
21. Port 993 – IMAPS (IMAP over SSL/TLS): Secure email retrieval.
22. Port 995 – POP3S (POP3 over SSL/TLS): Secure email retrieval.
23. Port 137-139 – NetBIOS: Communication between Windows machines.
24. Port 2049 – NFS (Network File System): File sharing.
25. Port 2181 – ZooKeeper: Coordination service for distributed systems.
26. Port 3306 – MySQL: Database connections with MySQL.
27. Port 3690 – SVN (Subversion): Version control system.
28. Port 389 – LDAP (Lightweight Directory Access Protocol): Directory services.
29. Port 6881-6889 – BitTorrent: Peer-to-peer file sharing.
30. Port 5432 – PostgreSQL: Database connections with PostgreSQL.

These well-known ports facilitate the standardized and efficient exchange of data between computers and devices on the internet and local networks. Network administrators and security professionals often use port information to configure firewalls and routing rules to control and monitor network traffic.