🖥️ Linux Server Initial Setup Guide

This guide walks you through the essential steps for setting up a new Linux server, focusing on security and best practices.

Prerequisites

A fresh Linux server (Ubuntu 22.04 LTS recommended)
Root or sudo access
SSH client

Step 1: Update System Packages

Always start by updating your system:

# Update package lists
sudo apt update
 
# Upgrade installed packages
sudo apt upgrade -y
 
# Install essential tools
sudo apt install -y curl wget git vim htop

Step 2: Create a Non-Root User

Never use the root account for daily operations:

# Create new user
sudo adduser devops
 
# Add to sudo group
sudo usermod -aG sudo devops
 
# Switch to new user
su - devops

Step 3: Configure SSH Security

Edit the SSH configuration for enhanced security:

sudo vim /etc/ssh/sshd_config

Apply these settings:

# Disable root login
PermitRootLogin no
 
# Disable password authentication (after setting up SSH keys)
PasswordAuthentication no
 
# Change default port (optional)
Port 2222
 
# Limit login attempts
MaxAuthTries 3

Restart SSH service:

sudo systemctl restart sshd

Step 4: Set Up Firewall (UFW)

# Install UFW
sudo apt install ufw
 
# Default policies
sudo ufw default deny incoming
sudo ufw default allow outgoing
 
# Allow SSH
sudo ufw allow 2222/tcp
 
# Allow HTTP/HTTPS
sudo ufw allow 80/tcp
sudo ufw allow 443/tcp
 
# Enable firewall
sudo ufw enable
 
# Check status
sudo ufw status verbose

Step 5: Install Fail2Ban

Protect against brute-force attacks:

# Install fail2ban
sudo apt install fail2ban
 
# Create local config
sudo cp /etc/fail2ban/jail.conf /etc/fail2ban/jail.local
 
# Start and enable
sudo systemctl start fail2ban
sudo systemctl enable fail2ban

Step 6: Configure Automatic Updates

# Install unattended-upgrades
sudo apt install unattended-upgrades
 
# Enable automatic updates
sudo dpkg-reconfigure -plow unattended-upgrades

Summary Checklist

Task	Status
System updated	✅
Non-root user created	✅
SSH hardened	✅
Firewall configured	✅
Fail2ban installed	✅
Auto-updates enabled	✅

🔐 Security Note: Always keep your server updated and regularly audit your security configurations.

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