Well-known ports, TCP vs UDP. Relevant for Network+, Security+, CCNA.
Port numbers are pure recall, and recall is what rapid-fire drilling is for. Subbing asks the port for a service, the service for a port, whether it runs over TCP or UDP, which port range a number belongs to, and the port of the secure replacement (HTTPS, IMAPS, LDAPS, SFTP).
The table has 146 ports in four sets. Exam core is the classic list behind the certifications. The nmap top 100 set covers the services a port scan finds most often. Databases, admin and cloud adds Postgres, Redis, Kubernetes and the rest. The industrial set is for people who work on plants: Modbus, S7comm, DNP3, EtherNet/IP, BACnet, OPC UA, PROFINET and more.
The full list is on the ports cheat sheet, grouped by set with a one-line note each.
Generated by the same code as the app. They change with every release; the app never runs out.
Ports cheat sheet: all 146 ports, grouped by set, with the transport and a one-line note.
TCP 443. HTTP is 80. The secure variants of the mail protocols are 993 (IMAPS), 995 (POP3S) and 465 (SMTPS); 587 is SMTP submission with STARTTLS.
Both, on port 53. Queries are UDP; zone transfers and responses over 512 bytes without EDNS use TCP.
Modbus TCP is 502, Siemens S7comm is 102, DNP3 is 20000, EtherNet/IP is 44818 (with I/O on 2222/UDP), BACnet/IP is 47808/UDP and OPC UA is 4840. All of them are in the Industrial / OT set.