In this guide, I will list the most common TCP & UDP ports and provide you with a downloadable Common Ports Cheat Sheet (PDF).
IANA is a standards organization that oversees global IP address allocation and classifies TCP & UDP ports. There is a total of 65,535 tcp/udp ports and they are divided into the following three classes:
Ports 1 to 1,023 (Well Known Ports)
These are reserved ports in the range of 1 to 1,023 and have been registered with IANA for a specific service.
Ports 1,024 to 49,151 (Registered Ports)
This range is also registered with IANA but is not as commonly used.
Ports 49152 to 65535 (Dynmaic and/or private ports)
IANA reserves this port range for dynamic use for proprietary services or private use.
What are the Most Commonly Used Ports?
It’s important to know what common ports are used, this can be helpful as a Network Administrator when working with Firewalls, security analysis, and when running port scans such as Nmap.
Here is the PDF version of the Top 100 Common Ports. You can click the link or the image below to download the PDF.
Top 25 Most Popular Ports
From the top 100 these are the 25 most popular ports (most frequently used).
- Port 80 TCP – (HTTP)
- Port 443 TCP – (HTTPS)
- Port 67-68 UDP – (DHCP)
- Port 20-21 – (FTP)
- Port 23 – (Telnet)
- Port 22 – (SSH)
- Port 53 TCP/UDP – (DNS)
- Port 8080
- Port 123 UDP – (NTP)
- Port 25 TCP – (SMTP)
- Port 3389 TCP (RDP)
- Port 110 TCP – (POP3)
- Port 554 TCP/UDP – (RTSP)
- Port 445 – (SMB/Cifs)
- Port 587
- Port 993 TCP – (IMAPS)
- Port 137-139 – (NetBois)
- Port 8008
- Port 500 UDP – (SIP)
- Port 143
- Port 161-162 UDP – (SNMP)
- Port 389 TCP – (LDAP)
- Port 1434 UDP – (Microsoft SQL)
- Port 5900 TCP – (VNC)