Always open a second SSH session before changing
sshd_config.1. Enable the service
chmod +x /etc/rc.d/rc.sshd
/etc/rc.d/rc.sshd start2. Keys and authorized_keys
mkdir -p ~/.ssh
chmod 700 ~/.ssh
cat key.pub >> ~/.ssh/authorized_keys
chmod 600 ~/.ssh/authorized_keys3. Basic sshd_config options
PermitRootLogin no
PubkeyAuthentication yes
PasswordAuthentication no
AllowUsers adminuser4. Test and restart
sshd -t
/etc/rc.d/rc.sshd restartIf
sshd -t is clean, the restart is safe. Test login in a new session before closing the current one.5. Checks
ss -tulpen | grep ':22'
grep sshd /var/log/messages | tail -n 30Quick checklist
[ ] rc.sshd enabled
[ ] keys installed
[ ] sshd_config tested with sshd -t
[ ] rc.sshd restarted
[ ] key login verified