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Ubuntu 24.04 Initial Setup & Hardening Guide

A concise, step-by-step guide for securing and configuring a fresh Ubuntu 24.04 server.

Alternatively you can skip the text and use the cloud-init script files cloud-init.yaml, cloud-init-docker.yaml, cloud-init-lemp.yaml, or cloud-init-nginx-proxy.yml for an automated setup.

Base Installation

• Deploy the official Ubuntu 24.04 LTS image from your cloud provider or ISO.
• Log in as the default user (or via SSH key if provided).

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Nginx Reverse Proxy with Let’s Encrypt (Certbot Standalone) & TLS Hardening

This guide shows how to use Nginx as a reverse proxy with a legitimate Let’s Encrypt certificate, using Certbot in standalone mode (no need to reconfigure Nginx for HTTP-01 challenge). It also covers certificate renewal testing and TLS hardening in Nginx.

Prerequisites

• Ubuntu 22.04/24.04 server (or similar)
• Domain name pointed to your server’s public IP
• Nginx installed (sudo apt install nginx)
• Ports 80 and 443 open in your firewall

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Install Mautic on Ubuntu 24.04 LEMP Server

This guide assumes you have provisioned your server with a LEMP stack (Nginx, MariaDB, PHP 8.3) using cloud-init-lemp.yml. It covers secure MariaDB setup, Composer installation, Mautic deployment, and HTTPS configuration for mautic.example.com.

1. Secure MariaDB and Create Database/User

Set your passwords and database info as needed. Replace all placeholders!

# Secure MariaDB (set root password, remove test DB, etc.)

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Resize the Volume of an Ubuntu Cloud Instance e.g. on Scaleway

First check that you have the cloud-guest-utils package installed:

dpkg -l | grep cloud-guest-utils

If it is not installed, you can install it with:

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Enable Swap on Ubuntu

Create a swap file on Ubuntu to increase system performance by allowing the system to use disk space as virtual memory.

Create a 2GB swap file:

sudo fallocate -l 2G /swapfile

If fallocate is not available, you can use dd:

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Date & Time Formatting Cheat Sheet (PHP vs Linux vs Ruby/Rails vs Standards)

This guide provides equivalent date/time format strings across popular environments (PHP, Linux, Ruby, etc.), with examples and tips. Also includes standard formats like ISO 8601 and RFC 2822.

Common Display Formats

Format Purpose	PHP Format	Linux/Ruby/POSIX Format	Example Output
Full Date/Time	d-m-Y H:i T	%d-%m-%Y %H:%M %Z	05-07-2025 14:23 CEST
Short Date	d-m-Y	%d-%m-%Y	05-07-2025

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Setup Redis Object Cache for WordPress

Install Redis Server

apt update
apt install redis-server -y

Check Redis is running: systemctl status redis