Choosing the SSH authorized-key file | LinuC Level 1 102 Exam original practice question

1.10.3Basic

On the server, permit trainee to authenticate with a public key using the normal OpenSSH home-directory setup.

Which file should receive the key?

Hint 1: Focus on the key relationship

Identify who must decrypt the data, then distinguish confidentiality, authentication, and the direction of each key operation.

Hint 2: Key terms

Review the short definitions of SSH keys, forwarding directions, encryption, and signatures involved.

authorized_keys: The file sshd consults to allow a user's public-key authentication.
known_hosts: The file where an SSH client records keys presented by remote hosts.
Host key: A key that identifies an SSH server to connecting clients.
sshd: The server daemon that accepts SSH connections and processes authentication.
Public-key authentication: An authentication method in which a private key proves possession and a public key verifies it.

Detailed explanation

Incorrect~trainee/.ssh/known_hosts

Incorrect. known_hosts records remote host keys for the client.

Incorrect/etc/ssh/ssh_host_rsa_key.pub

Incorrect. This is the server's own host public key.

Incorrect~trainee/.ssh/config

Incorrect. config is a client-side connection configuration file.

Correct~trainee/.ssh/authorized_keys

Correct. authorized_keys lists public keys allowed for the user.

Try it yourself

An example you can run in a temporary verification environment.

tmp=$(mktemp -d); mkdir -p "$tmp/.ssh"; touch "$tmp/.ssh/authorized_keys"; test -f "$tmp/.ssh/authorized_keys" && printf 'authorized_keys\n'; rm -rf "$tmp"

Expected result

authorized_keys

Key points

authorized_keys
known_hosts is different
Host key is different

Notes

Environment: OpenSSHのファイル役割 / 一時ディレクトリ
Command output formatting can vary slightly by distribution or tool version.
Run the example in a temporary directory or process when possible.

Foundation review

Host key

A server identity key used by SSH clients to detect a changed endpoint.

User key

A key pair used to authenticate a user to an SSH server.

Port forwarding

An SSH tunnel that carries traffic between a local, remote, or dynamic endpoint.

Question IDKL-102-1151

EnvironmentOpenSSHのファイル役割 / 一時ディレクトリ

Last technical review2026-08-20

Report an error or rights issue