Password authentication is the weakest link in SSH security. Generate an SSH key pair with ssh-keygen -t ed25519. Copy the public key with ssh-copy-id user@your-server. Then disable password authentication in /etc/ssh/sshd_config: set PasswordAuthentication no and ChallengeResponseAuthentication no. Restart SSH and verify key login works before closing your session. This single change eliminates the vast majority of SSH brute-force attacks that every internet-facing VPS receives.
Switch to Key-Based Authentication
Password authentication is the weakest link in SSH security. Generate an SSH key pair with ssh-keygen -t ed25519. Copy the public key with ssh-copy-id user@your-server. Then disable password authentication in /etc/ssh/sshd_config: set PasswordAuthentication no and ChallengeResponseAuthentication no. Restart SSH and verify key login works before closing your session. This single change eliminates the vast majority of SSH brute-force attacks that every internet-facing VPS receives.
Additional Hardening Steps
Change the default SSH port from 22 to a high port number to avoid automated scanners. Disable root login with PermitRootLogin no. Limit SSH access to specific users with AllowUsers yourusername. Set idle timeouts with ClientAliveInterval 300 and ClientAliveCountMax 2. Install Fail2ban to automatically ban IPs after failed login attempts: apt install fail2ban. These layered defenses make your VPS extremely resistant to unauthorized access.
Ongoing Security Monitoring
Review /var/log/auth.log regularly for suspicious activity. Set up log-based alerting for successful logins from unfamiliar IPs. Keep your SSH server updated to patch any vulnerabilities. With Velox Media’s custom solutions for demanding workloads, you have the infrastructure foundation — these SSH hardening steps add the application-level security that completes your defense-in-depth strategy.
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