SK0-004 · Question #373
A server technician needs to access a remote Unix server for administration. The technician has requested that ports 23. 25, and 161 be opened on the router. After the ports are opened, the…
The correct answer is B. TCP 22. Remote administration of a Unix server requires SSH on TCP 22; the ports opened (Telnet 23, SMTP 25, SNMP 161) do not provide interactive shell access.
Question
A server technician needs to access a remote Unix server for administration. The technician has requested that ports 23. 25, and 161 be opened on the router. After the ports are opened, the technician is still unable to connect to the Unix server. Which of the following ports should be opened on the server to allow for remote administration?
Options
- ATCP 21
- BTCP 22
- CUDP 69
- DTCP 3389
How the community answered
(52 responses)- A2% (1)
- B85% (44)
- C4% (2)
- D10% (5)
Why each option
Remote administration of a Unix server requires SSH on TCP 22; the ports opened (Telnet 23, SMTP 25, SNMP 161) do not provide interactive shell access.
TCP 21 is the FTP control port used for file transfers and does not provide remote shell access or administrative command-line capabilities on a Unix server.
TCP 22 is the standard port for SSH (Secure Shell), the primary protocol for secure, encrypted remote administration of Unix and Linux systems. The ports the technician requested - Telnet (23), SMTP (25), and SNMP (161) - serve monitoring, mail relay, and legacy terminal functions but do not enable an authenticated interactive shell session required for server administration.
UDP 69 is TFTP (Trivial File Transfer Protocol), a simple unauthenticated file transfer service with no remote administration capability.
TCP 3389 is the port for RDP (Remote Desktop Protocol), a Windows-specific graphical remote access protocol that is not used for remote administration of Unix servers.
Concept tested: SSH port for Unix remote server administration
Source: https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml
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