N10-005 · Question #404
Which of the following services are affected by closing the default ports of 80 and 21 via ACL on a company router?
The correct answer is A. FTP and basic Internet traffic. Port 80 is HTTP (basic web traffic) and port 21 is FTP; blocking both via ACL would disrupt HTTP browsing and FTP file transfers.
Question
Which of the following services are affected by closing the default ports of 80 and 21 via ACL on a company router?
Options
- AFTP and basic Internet traffic
- BHTTPS and IMAP traffic
- CDNS and TELNET traffic
- DVPN and RDP traffic
How the community answered
(35 responses)- A91% (32)
- B3% (1)
- C3% (1)
- D3% (1)
Why each option
Port 80 is HTTP (basic web traffic) and port 21 is FTP; blocking both via ACL would disrupt HTTP browsing and FTP file transfers.
Port 21 is the well-known control port for FTP, and port 80 is the well-known port for HTTP (unencrypted web traffic). Blocking these two ports via an ACL on the router would prevent standard file transfer via FTP and standard unencrypted web browsing, directly matching the description.
HTTPS uses port 443 and IMAP uses port 143; neither maps to port 80 or 21.
DNS uses port 53 and Telnet uses port 23; neither maps to port 80 or 21.
VPN protocols use various ports (e.g., 1194, 500) and RDP uses port 3389; neither maps to port 80 or 21.
Concept tested: Well-known port numbers for HTTP and FTP services
Source: https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml
Topics
Community Discussion
No community discussion yet for this question.