Secure your Linux VPS

Switch from password-based login to public/private key authentication using ssh key pairs. Generate keys on the client, copy the public key to the server, and disable password authentication.

Hardening sshd_config by disabling root login and x11 forwarding, blocking port forwarding, and enforcing protocol 2. Use public/private keys and disable passwords, with max 3 sessions and limited login attempts.

Two factor authentication adds a second token that changes every 30 seconds, requiring something you know (password) and something you have (hardware key or mobile app) to log in.

install google authenticator, configure time-based tokens, scan qr codes, and save emergency keys; enable password authentication with two-factor authentication in sshd.

Learn to secure a Linux VPS by enabling Google Authenticator based two-factor authentication with SSH key pairs, disabling password authentication, configuring sshd, and restarting the SSH service.

Limit who can use sudo by managing the sudo group and editing sudo configuration. Check groups, add users to sudo, and ensure only group members can execute commands.

Install and configure the network time protocol (ntp) client on a Linux server, verify time with pool servers, and restart the service to ensure accurate system time.

Learn how to install and configure ufw on Ubuntu or Debian, enforce a default deny policy, and selectively allow SSH, DNS, NTP, and web traffic to secure a Linux server.

Learn how fail2ban monitors your network, blocks attackers after repeated failed logins, installs and configures bans with jail rules, ignores trusted IPs, and checks status or unbans as needed.

Psad is an intrusion detection and prevention system that monitors network activity and blocks repeated intrusion attempts on a Linux vps.

Learn to use Lynis to audit Linux systems, install it from the Debian or Ubuntu repository, and run scans that report system status and hardening recommendations, including a malware scanner.

Install and run rkhunter on a Debian system to scan your Linux VPS for rootkits and malware, review scan results (watch for false positives), and configure daily scans and updates.

Install chkrootkit on Debian or Ubuntu and run a manual scan with sudo chkrootkit to detect rootkits, then configure automatic daily scans and email alerts.