In modern networking and cybersecurity, understanding network ports is essential for system administrators, network engineers, and penetration testers. In computer networking Ports act as communication endpoints that allow
In computer networking Ports act as communication endpoints that allow services like web servers, email, and remote access to function properly. Misconfigured or exposed ports are also one of the most common entry points for cyberattacks.
This guide covers the top 50 most important ports every IT professional should know — including their purpose, real-world usage, and security risks.
A port is a logical channel used by protocols like TCP/UDP to identify specific services on a device.
A port is just a logical door on a device that allows different types of network traffic to enter or leave. Every computer or server uses IP addresses to find each other, but ports decide which service on that system should handle the request.
| Port | Protocol | Service | Purpose |
|---|---|---|---|
| 25 | SMTP | Simple Mail Transfer Protocol | Email sending between servers |
| 53 | DNS | Domain Name System | Domain name resolution (website → IP) |
| 67/68 | DHCP | Dynamic Host Configuration Protocol | Automatic IP address assignment (67 = server, 68 = client) |
| 69 | TFTP | Trivial File Transfer Protocol | Simple file transfer (no authentication) |
| 80 | HTTP | HyperText Transfer Protocol | Standard web traffic |
| 110 | POP3 | Post Office Protocol v3 | Email retrieval (downloads emails) |
| 119 | NNTP | Network News Transfer Protocol | Usenet/newsgroup communication |
| 123 | NTP | Network Time Protocol | Time synchronization across systems |
| 135 | RPC | Remote Procedure Call | Windows service communication |
| 137–139 | NetBIOS | Network Basic Input/Output System | Windows file/printer sharing |
| 143 | IMAP | Internet Message Access Protocol | Advanced email management (sync across devices) |
| 161/162 | SNMP | Simple Network Management Protocol | Network monitoring and device management |
| 443 | HTTPS | HTTP Secure | Encrypted web traffic (secure browsing) |
| 514 | Syslog |
System Logging Protocol
|
Centralized log collection |
| Port | Protocol / Service | Category | Purpose |
|---|---|---|---|
| 1080 | SOCKS Proxy | Proxy Service | Routes traffic through proxy server |
| 1194 | OpenVPN | VPN | Secure encrypted VPN tunneling |
| 1241 | Nessus | Security Scanner | Vulnerability scanning (Nessus engine) |
| 1433 | MS SQL | Database | Microsoft SQL Server database access |
| 1521 | Oracle DB | Database | Oracle database connection service |
