6.1 Hardening del Servidor OpenSSH
Directivas seguras en /etc/ssh/sshd_config.d/99-hardening.conf:
# Solo autenticación por clave pública Ed25519
Port 2222
PermitRootLogin no
PasswordAuthentication no
KbdInteractiveAuthentication no
PubkeyAuthentication yes
MaxAuthTries 3
ClientAliveInterval 300
ClientAliveCountMax 2
AllowGroups sysadmins