Port > System Ports

System ports are part of the well-known port range, specifically ports 0 to 1023. These ports are assigned by the Internet Assigned Numbers Authority (IANA) and are standardized for use with widely-recognized network services and protocols. System ports play a crucial role in network communication and are essential for enabling various network services to operate efficiently. Here are some common system ports and their associated services:

1. Port 0: Reserved and not used for any specific service. It’s sometimes called the “null” port.
2. Port 20/21: FTP (File Transfer Protocol) – Used for transferring files between a client and a server.
3. Port 22: SSH (Secure Shell) – Provides secure remote access and control of a computer over a network.
4. Port 23: Telnet – Used for remote command-line access to a computer.
5. Port 25: SMTP (Simple Mail Transfer Protocol) – Handles the sending of email messages.
6. Port 53: DNS (Domain Name System) – Resolves domain names to IP addresses.
7. Port 67/68: DHCP (Dynamic Host Configuration Protocol) – Assigns and manages IP addresses on a network.
8. Port 69: TFTP (Trivial File Transfer Protocol) – A simplified version of FTP for basic file transfer.
9. Port 80: HTTP (Hypertext Transfer Protocol) – Used for standard web browsing.
10. Port 110: POP3 (Post Office Protocol version 3) – Retrieves email messages from a mail server.
11. Port 123: NTP (Network Time Protocol) – Synchronizes the time of a computer with a time server.
12. Port 135: MS RPC (Microsoft Remote Procedure Call) – Facilitates communication between Windows systems.
13. Port 137-139: NetBIOS – Supports communication between Windows machines.
14. Port 143: IMAP (Internet Message Access Protocol) – Retrieves email messages from a mail server.
15. Port 161: SNMP (Simple Network Management Protocol) – Used for network management and monitoring.
16. Port 194: IRC (Internet Relay Chat) – Supports real-time chat communication.
17. Port 443: HTTPS (HTTP over SSL/TLS) – Provides secure web browsing.
18. Port 445: SMB (Server Message Block) – Enables file and printer sharing in Windows networks.
19. Port 465/587: SMTP over SSL/TLS – Secure transmission of email.
20. Port 514: Syslog – Collects and forwards system log messages.

These system ports are crucial for network communication, as they ensure that widely-recognized network services and protocols can operate efficiently and with standardization. Network administrators and security professionals often use port information to configure firewalls and routing rules to control and monitor network traffic.