Common Network Ports Cheat Sheet

A port number says which service on a machine a connection is meant for. Together with an IP address it identifies one endpoint, such as 203.0.113.5:443. Below are the ports you will meet most often. To look up any port, use the Port Number Lookup.

Port ranges

Common ports

Reading the table

• TCP vs UDP. TCP is reliable and ordered (web pages, mail, databases); UDP is faster and lossy (DNS lookups, time sync, VPNs, streaming). Some services use both.
• Encrypted twins. Many protocols come in a plain and a TLS flavour on different ports: HTTP 80 and HTTPS 443, IMAP 143 and IMAPS 993, LDAP 389 and LDAPS 636.
• A port is only a convention. Nothing stops a service listening somewhere else, and an open port does not prove which program is behind it.

Security notes

Expose only the ports a service actually needs. Management and database ports such as 22, 445, 1433, 3306, 3389, 5432, 6379 and 27017 should sit behind a Firewall or VPN, not face the public internet. To see which of your ports answer, use a scanner you are authorised to run; the TCP/UDP Port Range Generator helps write the ranges for firewall rules.