CyberCertPrepSecurity FundamentalsNetworking FundamentalsEASYFree question
What are the well-known port numbers for HTTP, HTTPS, SSH, FTP, and DNS?
- A.HTTP=443, HTTPS=80
- B.HTTP=80, HTTPS=443, SSH=22, FTP=21 (control)/20 (data), DNS=53 - these are well-known ports (0-1023) assigned by IANA and are essential knowledge for network security professionals
- C.HTTP=8080, HTTPS=8443; an access control list applied to an interface is evaluated from its bottom entry upward, and processing continues past the first match with the final line deciding the outcome
- D.All services use port 80, because port numbers below 1024 are reserved for client applications and are picked at random by the operating system for each outbound connection, while servers listen on ephemeral ports above 49152 that are published in the DNS service record for the zone
Why B is correct
Essential ports: HTTP(80), HTTPS(443), SSH(22), FTP(21/20), DNS(53), SMTP(25), POP3(110), IMAP(143), RDP(3389), Telnet(23), SNMP(161), LDAP(389), MySQL(3306), PostgreSQL(5432), SMB(445). Well-known ports: 0-1023, registered: 1024-49151, dynamic: 49152-65535.
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