Agent forwarding

Forward local SSH agent to the remote host (use with caution)

ssh -A user@bastion
tool
ssh15 commands
tags
sshsecurity

More ssh commands

  • Add key to agent
    eval $(ssh-agent) && ssh-add ~/.ssh/id_ed25519

    Start agent and load a key for the session

  • SSH config file host entry
    cat >> ~/.ssh/config <<'EOF' Host dev HostName 10.0.0.5 User ubuntu IdentityFile ~/.ssh/dev_key ProxyJump bastion EOF

    Shorthand alias: 'ssh dev' triggers all options

  • Escape sequences in session
    ~.

    Terminate a frozen/hung SSH session: type tilde then dot

  • Check SSH server host key
    ssh-keyscan -t ed25519,rsa host 2>/dev/null | ssh-keygen -lf -

    Fetch and fingerprint server host keys without connecting

  • Restrict authorized key
    echo 'from="10.0.0.0/8",no-agent-forwarding,no-port-forwarding,command="/usr/bin/backup.sh" <pubkey>' >> ~/.ssh/authorized_keys

    Force-command and restrict source IP in authorized_keys

all 15 ssh commands