Linux Security Guide 🐧🔐

1. What is Linux Security?

Linux security involves protecting systems, users, and data from unauthorized access and attacks.

2. User Management

adduser username
passwd username
usermod -aG sudo username

3. File Permissions

chmod 755 file
chown user file

4. Firewall

sudo ufw enable
sudo ufw allow 22
sudo ufw status

5. SSH Security

Disable root login
Use SSH keys
Change default port

6. Updates & Patching

sudo apt update
sudo apt upgrade

7. Monitoring

top
htop
journalctl

8. Best Practices

- Strong passwords
- Least privilege
- Regular backups
- Disable unused services