200-301 · Question #859
By default, which port is the following telnet command going to? C:\Windows\system32> telnet 2001:DB8:172:16::100
The correct answer is A. 23. This question asks for the default TCP port number used by the telnet client command when no specific port is specified.
Question
Options
- A23
- B21
- C80
- D43
How the community answered
(33 responses)- A88% (29)
- B3% (1)
- C3% (1)
- D6% (2)
Why each option
This question asks for the default TCP port number used by the telnet client command when no specific port is specified.
The Telnet protocol, by industry standard and IANA assignment, utilizes TCP port 23 for establishing remote terminal connections when no alternative port is explicitly provided in the command. This default applies regardless of whether an IPv4 or IPv6 address is used.
Port 21 is the default port for the File Transfer Protocol (FTP) control connection, not Telnet.
Port 80 is the default port for the Hypertext Transfer Protocol (HTTP), used for web traffic, not Telnet.
Port 43 is the default port for the WHOIS protocol, used for querying databases for domain registration information, not Telnet.
Concept tested: Default Telnet port
Source: https://www.iana.org/assignments/port-numbers-cisco/port-numbers-cisco.xhtml
Topics
Community Discussion
No community discussion yet for this question.