What port does SSH use?

SSH uses TCP port 22. It replaced Telnet (TCP 23) for encrypted remote CLI access.

DNS uses port 53 over both UDP and TCP. UDP 53 handles most lookups; TCP 53 is used for zone transfers and responses larger than 512 bytes.

What ports does DHCP use?

DHCP uses UDP port 67 on the server and UDP port 68 on the client.

[ GAME · PORTS · DOMAIN 4 ]

PORTGUESSER_

Guess the port before you run out of lives. Service to port, port to service, TCP vs UDP, and the secure replacement for legacy protocols — the port numbers the CCNA loves to test, drilled fast.

◀ ALL GAMES

★ PORT CHEAT NOTES

[ WHAT THIS DRILLS ] SSH 22 · Telnet 23 · HTTP 80 · HTTPS 443 · DNS 53 (TCP/UDP) · DHCP 67/68 UDP · FTP 20/21 · TFTP 69 UDP · SMTP 25 · POP3 110 · IMAP 143 · SNMP 161 / trap 162 UDP · NTP 123 UDP · RADIUS 1812/1813 UDP · TACACS+ 49 TCP · LDAP 389 / LDAPS 636 · Kerberos 88 · Syslog 514 UDP · RDP 3389 · BGP 179 TCP · RIP 520 UDP. Plus the routing/security protocols that ride directly on IP with no port: OSPF (89), EIGRP (88), GRE (47), ESP (50), AH (51), and ICMP (no port).

Why ports matter for the CCNA. Port numbers show up across security ACLs, NAT, and troubleshooting. Knowing TCP vs UDP and the secure replacement for legacy protocols (Telnet → SSH, HTTP → HTTPS, SNMPv2 → SNMPv3, LDAP → LDAPS) is fast, free marks on exam day.

How to play. Pick Endless to survive on three lives, or Daily 10 for a fixed set that's the same for everyone today. Tap an answer or press 1-4. Every answer shows a one-line explanation.