Port Numbers — Cisco CCNA (200-301) Practice Questions
Port numbers are 16-bit identifiers used at the transport layer to distinguish between different application-layer services running on the same host, enabling multiplexing of multiple simultaneous connections. The CCNA 200-301 exam requires candidates to memorize well-known port numbers for common protocols, including FTP (20/21), SSH (22), Telnet (23), DNS (53), DHCP (67/68), HTTP (80), HTTPS (443), and SNMP (161), among others. Port numbers are tested in questions about access control lists, firewall rules, and protocol identification. Understanding the difference between well-known, registered, and dynamic port ranges is also part of the expected knowledge.
Free questions on port numbers
What is the port number range for well-known ports?
Free question · easy · full answer + explanation
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