Adding a private key to ssh-agent | LinuC Level 1 102 Exam original practice question

1.10.3Basic

Use ssh-agent so a generated key's passphrase need not be entered repeatedly.

Which command is appropriate?

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.

ssh-agent: A process that holds private keys and performs signing on behalf of SSH clients.
ssh-add: A command that registers an existing private key with ssh-agent.
Agent forwarding: A feature that relays signing requests to an agent on the originating host.
Private key: The non-distributable half of a public/private authentication pair.
Agent socket: A local communication endpoint through which clients contact an SSH agent.

Detailed explanation

Correctssh-add ~/.ssh/id_ed25519

Correct. ssh-add registers the private key.

Incorrectssh-keygen -A

Incorrect. ssh-keygen -A generates host keys.

Incorrectssh-agent -a ~/.ssh/id_ed25519

Incorrect. ssh-agent -a selects the agent socket.

Incorrectssh -A ~/.ssh/id_ed25519

Incorrect. ssh -A enables agent forwarding for a connection.

An example you can run in a temporary verification environment.

printf '%s\n' 'ssh-add ~/.ssh/id_ed25519'

ssh-add ~/.ssh/id_ed25519

Foundation review

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

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

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

Question IDKL-102-1152

EnvironmentOpenSSH clientのコマンド役割

Last technical review2026-08-20

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