1.07.1Basic
Connect to an SSH server listening on its standard TCP port.
The server port has not been changed.
Which destination port is used?
× Incorrect
SSH uses TCP port 22 by default. An administrator may configure a different port in the server settings.
Detailed explanation
Incorrect21
Incorrect. 21/tcp is FTP control.
Incorrect. 21/tcp is FTP control.
Incorrect23
Incorrect. 23/tcp is Telnet.
Incorrect. 23/tcp is Telnet.
Correct22
Correct. 22/tcp is SSH's standard port.
Correct. 22/tcp is SSH's standard port.
Incorrect25
Incorrect. 25/tcp is SMTP.
Incorrect. 25/tcp is SMTP.
Try it yourself
An example you can run in a temporary verification environment.
getent services ssh | sed -n '1p'Expected result
ssh 22/tcpを示すサービスデータベース行Key points
- SSH is 22/tcp
- Telnet is 23/tcp
- Configuration can change the port
Notes
- Environment: Linux NSS servicesデータベース / 外部通信なし
- Command output formatting can vary slightly by distribution or tool version.
- Run the example in a temporary directory or process when possible.
Foundation review
Read the scope first
Check whether the command acts on the current shell, a new process, an existing process, or a file.
Verify the observable result
Use the supplied command and compare the output with the expected result.
Question IDKL-102-947
EnvironmentLinux NSS servicesデータベース / 外部通信なし
Last technical review2026-08-13
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