Home on Manzolo Code Notes

SPF, DMARC and DKIM: The Email Security Triad

Mon, 16 Feb 2026 10:00:00 +0200

Understanding how SPF, DMARC, and DKIM work to protect your emails from spam and phishing

Manzolo PPA (My Own Ubuntu Repository)

Sat, 08 Nov 2025 18:30:00 +0200

Manzolo PPA — My Personal Ubuntu Repository

Install my tools directly with apt!
Secure, GPG-signed repository hosted at https://ubuntu-repo.manzolo.it

Ubuntu 26.04 (resolute) — FULLY SUPPORTED

wget -qO - https://ubuntu-repo.manzolo.it/KEY.gpg | sudo gpg --dearmor -o /etc/apt/trusted.gpg.d/manzolo-repo.gpg
echo "deb [arch=amd64 signed-by=/etc/apt/trusted.gpg.d/manzolo-repo.gpg] https://ubuntu-repo.manzolo.it resolute main" | sudo tee /etc/apt/sources.list.d/manzolo-repo.list
sudo apt update

Ubuntu 24.04 (noble) — FULLY SUPPORTED

wget -qO - https://ubuntu-repo.manzolo.it/KEY.gpg | sudo gpg --dearmor -o /etc/apt/trusted.gpg.d/manzolo-repo.gpg
echo "deb [arch=amd64 signed-by=/etc/apt/trusted.gpg.d/manzolo-repo.gpg] https://ubuntu-repo.manzolo.it noble main" | sudo tee /etc/apt/sources.list.d/manzolo-repo.list
sudo apt update

Install my packages

manzolo-chroot package

sudo apt install manzolo-chroot

Search all my tools

apt search manzolo

Verify everything works

apt policy | grep manzolo

Remove the repository (if you ever want to)

sudo rm /etc/apt/sources.list.d/manzolo-repo.list
sudo rm /etc/apt/trusted.gpg.d/manzolo-repo.gpg
sudo apt update

Build Your Own Ubuntu Repository with Docker

Sat, 08 Nov 2025 08:30:00 +0200

Build Your Own Ubuntu Repository with Docker 📦

Ever wanted to distribute your own software packages just like Ubuntu does? Whether you’re managing internal tools across multiple servers, creating a private package distribution system, or just want to learn how APT repositories work under the hood, building your own Ubuntu repository is easier than you might think.

In this guide, I’ll show you how to create a production-ready Ubuntu repository using Docker, complete with GPG signing, automated publishing, and a web interface for package distribution.

Installing NVIDIA Container Toolkit

Tue, 04 Nov 2025 09:00:00 +0200

A guide to installing the NVIDIA Container Toolkit to enable GPU support for Docker containers

Docker Compose Playground

Sat, 11 Oct 2025 20:43:00 +0200

Docker Playground Manager 🐳

Introducing Docker Playground Manager, a powerful tool for managing Docker development environments! Spin up containers for testing, learning, or experimenting with 100+ pre-configured images (Linux, Python, PostgreSQL, etc.) using an interactive terminal UI.

What’s New? ✨

📚 MOTD guides for MySQL, PostgreSQL, and more.
🎯 Category-based container selection.
📺 New dashboard and enhanced stats.

Get Started 🚀

git clone https://github.com/manzolo/docker-compose-playground.git
cd docker-compose-playground
chmod +x playground.sh
./playground.sh

Explore the full feature set on GitHub. Try it out, share feedback, or contribute to make it even better!

Advanced Docker Compose Guide with Examples

Sat, 11 Oct 2025 09:00:00 +0200

Advanced Docker Compose Guide with Practical Examples

Introduction

Docker Compose is a powerful tool for defining and running multi-container applications. This guide explores advanced features using a real-world Flask + PostgreSQL application as the primary example.

What we’ll build: A production-ready web application with:

Flask web server
PostgreSQL database with migrations
pgAdmin for database management
Automated backups
Development and production configurations

Repository: docker-python-flask-postgres-template

SD Card Backup and Restore

Sun, 05 Oct 2025 14:30:00 +0200

Quick guide to backup and restore SD cards using dd and gzip compression

GPG Bash Playground

Sun, 28 Sep 2025 00:00:00 +0200

GPG Bash Playground Guide

Introduction

The GPG Bash Playground is an educational Bash script that demonstrates the practical use of GPG (GNU Privacy Guard) for key generation, public key exchange, encryption, and decryption. The script simulates a secure communication scenario by creating three users (Alice, Bob, and Carol), generating their GPG keys, exchanging public keys, and performing encrypted message exchanges. It includes comprehensive logging, error handling, and a debug mode for detailed output. This guide explains how to set up, run, and understand the script’s functionality.

Linux Boot Repair (Debian/Ubuntu)

Sat, 27 Sep 2025 15:34:00 +0200

Linux Boot Repair Guide (Debian/Ubuntu)

Introduction

Boot issues in Debian or Ubuntu can prevent your system from starting, often due to a corrupted GRUB bootloader, misconfigured partitions, or kernel problems. This guide provides step-by-step instructions to repair the boot process for both UEFI and Legacy (BIOS/MBR) systems using a live USB/CD. It covers GRUB reinstallation, partition setup, and troubleshooting common issues.

Prerequisites

A Debian or Ubuntu live USB/CD (preferably the same version as your system).
Access to a live session by booting from the live media and selecting “Try Ubuntu/Debian.”
Basic familiarity with the terminal.
Administrative (root) privileges in the live environment.

Critical Warning: Verify Partitions Before Formatting

⚠️Warning

Extreme Caution: Before formatting any partition, use lsblk or fdisk -l to verify that you are selecting the correct disk and partition (e.g., EFI System Partition or root partition). Formatting the wrong partition can erase your data or critical files. Always double-check the disk and partition layout to avoid data loss.

Linux Boot Repair

UEFI Boot Repair

UEFI systems use an EFI System Partition (ESP) to store GRUB and boot files. If the ESP is missing, corrupted, or misconfigured, the system may fail to boot.

Windows Boot Repair

Sat, 27 Sep 2025 15:26:00 +0200

Windows Boot Repair Guide

Introduction

Windows boot issues can prevent your system from starting correctly, often due to corrupted boot files, misconfigured partitions, or firmware settings. This guide provides step-by-step instructions to repair Windows boot problems for both UEFI and MBR/Legacy systems using the Windows Recovery Environment (WinRE) command prompt. It covers partition setup, boot configuration rebuilding, and troubleshooting common issues.

Prerequisites

A Windows installation USB or DVD with the same version as your system.
Access to the Windows Recovery Environment (WinRE) by booting from the installation media and selecting “Repair your computer.”
Basic familiarity with the Command Prompt.
Administrative privileges in the recovery environment.

Critical Warning: Verify Partitions Before Formatting

⚠️Warning

Extreme Caution: Before formatting any partition, use diskpart’s list disk and list part commands to verify that you are selecting the correct disk and partition (e.g., the EFI System Partition or system partition). Formatting the wrong partition can erase your Windows data or other critical files. Always double-check the disk and partition layout to ensure you are not deleting your data drive.

Windows Boot Repair

UEFI Boot Repair

UEFI systems use an EFI System Partition (ESP) to store boot files. If the ESP is missing, corrupted, or misconfigured, Windows may fail to boot.

Docker and Docker Compose

Fri, 26 Sep 2025 10:00:00 +0100

Docker and Docker Compose Guide

Introduction

Docker is a platform for developing, shipping, and running applications inside containers. Docker Compose is a tool for defining and running multi-container Docker applications using YAML files. This guide covers essential Docker and Docker Compose commands, with practical examples, to help you manage containers effectively.

What is Docker?

Docker allows you to package applications with their dependencies into containers, ensuring consistency across different environments. Containers are lightweight, portable, and run independently of the host system.

Git

Fri, 26 Sep 2025 10:00:00 +0100

Git and Gitflow Guide

Introduction

Git is a distributed version control system that enables multiple developers to collaborate on projects efficiently. Gitflow is a popular branching model that organizes Git branches for streamlined development and release management. This guide covers essential Git commands, introduces the Gitflow workflow, and provides practical examples for managing code repositories.

What is Git?

Git tracks changes to files, allowing multiple users to work on the same project without conflicts. It supports branching, merging, and version history, making it ideal for software development and collaborative projects.

Linux Sysadmin Commands Guide

Fri, 26 Sep 2025 10:00:00 +0100

Linux Sysadmin Commands Guide

Introduction

As a Linux system administrator, mastering essential commands is crucial for managing servers, monitoring systems, and troubleshooting issues. This guide covers fundamental Linux commands for system administration, focusing on user management, process control, network diagnostics, and system monitoring, with practical examples.

Prerequisites

A Linux system (e.g., Ubuntu, CentOS, or Debian).
Root or sudo privileges.
Basic familiarity with the terminal.

System Information

Hardware and System Overview

# Display system information
uname -a

# Show CPU details
lscpu
cat /proc/cpuinfo

# Display memory usage
free -h
cat /proc/meminfo

# List block devices (disks)
lsblk
fdisk -l # Requires sudo

# Show mounted filesystems
df -h

System Uptime and Load

# Display system uptime and load average
uptime

# Show load average
cat /proc/loadavg

# Interactive system monitoring
top
htop # If installed

User and Group Management

Managing Users

# Add a new user
sudo useradd -m -s /bin/bash username

# Set a password for the user
sudo passwd username

# Modify user details
sudo usermod -aG groupname username # Add user to a group
sudo usermod -s /bin/zsh username # Change shell

# Delete a user
sudo userdel -r username # Remove user and home directory

Managing Groups

# Create a new group
sudo groupadd groupname

# Add user to a group
sudo usermod -aG groupname username

# List groups
getent group

# Delete a group
sudo groupdel groupname

Example: Creating a User with Specific Permissions

Create a user devuser with sudo privileges:

QEMU Disk Image and VM Management Guide

Fri, 26 Sep 2025 10:00:00 +0100

QEMU Disk Image and VM Management Guide

Introduction

QEMU is a powerful open-source emulator and virtualizer for running virtual machines (VMs) and managing disk images on Linux systems. It supports a wide range of architectures and provides tools for creating, manipulating, and running VMs with flexible configurations. This guide covers essential QEMU commands for disk image management and VM operations, with practical examples for system administrators and developers.

Prerequisites

QEMU installed on a Linux system (qemu-system-x86_64 --version to verify).
Root or sudo privileges for certain operations (e.g., installing QEMU or accessing KVM).
Basic understanding of Linux terminal commands and virtualization concepts.

Install QEMU on Ubuntu/Debian:

SSH Forward Tunneling

Fri, 26 Sep 2025 10:00:00 +0100

SSH Forward Tunneling Guide

Introduction

SSH forward tunneling (also known as local port forwarding) allows you to securely connect to a remote service through an SSH server, making it appear as if the service is running on your local machine. This is useful for accessing services on a remote server or another machine in a secure network that aren’t directly accessible.

In this guide, we’ll cover the basics of SSH forward tunneling, explain how it works, and provide practical examples.

Uncomplicated Firewall

Fri, 26 Sep 2025 10:00:00 +0100

Ubuntu UFW Firewall Guide

Introduction

UFW (Uncomplicated Firewall) is a user-friendly interface for managing iptables firewall rules on Ubuntu systems. It simplifies the process of configuring firewall settings, making it accessible for beginners and efficient for advanced users. This guide covers essential UFW commands, practical examples, and tips for securing your Ubuntu server.

What is UFW?

UFW is a front-end for iptables, designed to make firewall configuration straightforward. It allows you to manage inbound and outbound network traffic by defining rules based on ports, protocols, and IP addresses.

Essential Bash Commands - File Management and System Analysis

Thu, 25 Sep 2025 10:00:00 +0100

Learn fundamental Bash commands for file management and system analysis that every developer should know

Basic Docker Compose Guide for Beginners (Debian/Ubuntu)

Sat, 11 Oct 2025 09:55:00 +0200

Basic Docker Compose Guide for Beginners (Debian/Ubuntu)

Introduction

Docker Compose is a tool for defining and running multi-container Docker applications using a simple YAML file. This beginner-friendly guide explains how to install Docker and Docker Compose on Debian/Ubuntu, create a basic docker-compose.yml file for a web application (Node.js) and database (PostgreSQL), run the application, and manage containers. It’s designed for users new to Docker who want to quickly set up a multi-container app.

Windows System Repair and Maintenance

Sun, 05 Oct 2025 15:00:00 +0200

Quick guide to repair corrupted Windows system files using SFC and DISM tools

Chroot Guide for Debian/Ubuntu

Sat, 27 Sep 2025 15:36:00 +0200

Chroot Guide for Debian/Ubuntu

Introduction

A chroot (change root) environment allows you to switch the root directory of a Linux session to a different filesystem, enabling you to work within a broken or inaccessible Debian/Ubuntu system as if it were the active system. This is particularly useful for repairing boot issues, recovering files, updating configurations, or resetting passwords. This guide provides step-by-step instructions to set up a chroot environment from a Debian/Ubuntu live USB/CD.

LUKS Encrypted Container

Sun, 05 Oct 2025 15:30:00 +0200

Quick guide to create and use LUKS encrypted containers for secure file storage on Linux

ZFS Pool Management Guide (Debian/Ubuntu)

Fri, 03 Oct 2025 10:00:00 +0200

ZFS Pool Management Guide (Debian/Ubuntu)

Introduction

ZFS (Zettabyte File System) is an advanced filesystem and volume manager for large storage pools, offering snapshots, compression, and redundancy (e.g., mirror, RAID-Z). This guide shows how to initialize disks with GPT, create a ZFS pool, use stable device identifiers (/dev/disk/by-id/ or /dev/disk/by-partuuid/), support various RAID types (mirror, RAID-Z1, RAID-Z2), and mount datasets for normal user access on Debian/Ubuntu.

⚡ Quick Start

ℹ️Info

New to ZFS? Start here:

APT Package Repository Management Guide

Sun, 05 Oct 2025 17:30:00 +0200

Complete guide to manage APT packages, identify repository sources, and audit installed packages on Debian/Ubuntu systems

Batch Image Optimization

Sun, 05 Oct 2025 16:00:00 +0200

Quick guide to batch optimize JPEG images for web use, reducing file size while maintaining quality

APT and DPKG Guide (Debian/Ubuntu)

Sat, 04 Oct 2025 12:00:00 +0200

APT and DPKG Guide (Debian/Ubuntu)

Introduction

apt and dpkg are core tools for package management on Debian and Ubuntu systems. apt update refreshes the package index from configured repositories, ensuring you have the latest package information. dpkg manages .deb packages, allowing direct installation, removal, querying, or identifying file ownership. This guide covers using apt update and dpkg, with use cases like system updates, manual .deb installation, searching for packages, finding file ownership, adding/removing external repositories, and determining which repository provides a package.

LVM RAID Management Guide (Debian/Ubuntu)

Fri, 03 Oct 2025 14:01:00 +0200

LVM RAID Management Guide (Debian/Ubuntu)

Introduction

Logical Volume Management (LVM) is a flexible storage management system that abstracts physical disks into logical volumes, allowing dynamic resizing, snapshots, and RAID configurations. LVM RAID integrates Linux software RAID (mdadm) with LVM to provide redundancy and flexibility. This guide explains how to create, modify, and manage an LVM setup with RAID on Debian/Ubuntu systems, covering volume group creation, logical volume setup with RAID, and maintenance tasks.

QEMU/VirtualBox Disk Resize

Sun, 05 Oct 2025 16:30:00 +0200

Quick guide to resize QEMU/VirtualBox virtual disks and expand partitions

Network Traffic Analysis with Wireshark (Debian/Ubuntu)

Sat, 04 Oct 2025 13:25:00 +0200

Network Traffic Analysis with Wireshark (Debian/Ubuntu)

Introduction

Wireshark is a powerful open-source tool for capturing and analyzing network traffic, widely used for debugging network issues, monitoring traffic, and security analysis. This guide explains how to install Wireshark on Debian/Ubuntu, capture traffic on a network interface, apply filters, and analyze packets for common protocols like HTTP and TCP. It includes practical examples for troubleshooting connectivity, inspecting web traffic, and identifying bandwidth usage.

LUKS Disk Encryption Management Guide (Debian/Ubuntu)

Fri, 03 Oct 2025 14:00:00 +0200

LUKS Disk Encryption Management Guide (Debian/Ubuntu)

Introduction

LUKS (Linux Unified Key Setup) is a standard for Linux disk encryption that provides a platform-independent way to encrypt block devices, such as partitions or entire disks. It supports multiple passphrases (keys), secure key derivation, and integration with other storage layers like LVM or ZFS. This guide explains how to create, modify, and manage encrypted disks with LUKS on Debian/Ubuntu systems, covering setup, key management, mounting, and maintenance.

Encrypted LVM Disk Resize (LUKS + LVM)

Sun, 05 Oct 2025 17:00:00 +0200

Quick guide to resize QEMU disks with LUKS encryption and LVM partitions

Network Traffic Analysis with tcpdump (Debian/Ubuntu)

Sat, 04 Oct 2025 13:35:00 +0200

Network Traffic Analysis with tcpdump (Debian/Ubuntu)

Introduction

tcpdump is a lightweight, command-line packet capture tool for analyzing network traffic on Linux systems. It’s ideal for server environments or quick diagnostics without a GUI, complementing tools like Wireshark. This guide covers installing tcpdump on Debian/Ubuntu, capturing traffic on a network interface, applying filters, saving captures to PCAP files, and analyzing them with tcpdump or Wireshark. It includes examples for monitoring HTTP traffic, debugging connectivity, and remote capturing.

ZSH Installation and Configuration Guide (Debian/Ubuntu)

Sat, 04 Oct 2025 00:22:00 +0200

ZSH Installation and Configuration Guide (Debian/Ubuntu)

Introduction

ZSH (Z Shell) is a powerful, customizable shell designed for interactive use and scripting, offering enhanced features over Bash, such as advanced autocompletion, themes, and plugins. This guide explains how to install ZSH, set up Oh My Zsh (a popular framework for managing ZSH configurations), and configure the Powerlevel10k theme with plugins like syntax highlighting and autosuggestions on Debian/Ubuntu systems. It provides a streamlined setup for a modern, user-friendly shell experience.

RDP Installation and Configuration Guide (Debian/Ubuntu)

Sat, 04 Oct 2025 00:26:00 +0200

RDP Installation and Configuration Guide (Debian/Ubuntu)

Introduction

Remote Desktop Protocol (RDP) enables remote access to a graphical desktop environment on a Linux system. XRDP is an open-source RDP server that allows connections from RDP clients (e.g., Windows Remote Desktop, Remmina) to a Debian/Ubuntu system. This guide explains how to install and configure XRDP with the XFCE desktop environment, a lightweight and efficient choice for remote desktops, on Debian/Ubuntu systems. It includes steps to set up a secure and functional RDP server for remote access.

OpenVPN Server Installation and Configuration Guide (Debian/Ubuntu)

Sat, 04 Oct 2025 11:00:00 +0200

OpenVPN Server Installation and Configuration Guide (Debian/Ubuntu)

Introduction

Setting up an OpenVPN server allows secure remote access to your network or resources. This guide explains how to install an OpenVPN server on Debian/Ubuntu, generate certificates and keys, configure the server, create user/client configurations, and connect from a client. It includes steps for creating multiple users and testing connections, making it ideal for home servers, small businesses, or secure remote access.

Mail Server Installation and Configuration Guide (Debian/Ubuntu)

Sat, 04 Oct 2025 11:00:00 +0200

Mail Server Installation and Configuration Guide (Debian/Ubuntu)

Introduction

Setting up a complete mail server allows you to send and receive emails using your own domain with full control over your data. This guide explains how to install and configure a production-ready mail server on Debian/Ubuntu with Postfix (SMTP), Dovecot (POP3/IMAP), user management, quota support, and security features including TLS/SSL encryption. It’s ideal for small businesses, organizations, or anyone wanting independent email hosting.

Wordpress backing up (files and database) and dockerizing

Sat, 27 Sep 2025 09:20:30 +0000

WordPress Management Script Usage Guide

Introduction

The wp-management script is a powerful Bash tool designed to streamline the management of WordPress sites. It supports two primary functions: backing up a WordPress site (including files and database) and dockerizing a WordPress site to run in a containerized environment with automatic restoration of backups. This guide explains the script’s purpose, how to use it, and provides practical examples to help you get started.

Home on Manzolo Code Notes

SPF, DMARC and DKIM: The Email Security Triad

Manzolo PPA (My Own Ubuntu Repository)

Manzolo PPA — My Personal Ubuntu Repository

Install my packages

manzolo-chroot package

Search all my tools

Verify everything works

Remove the repository (if you ever want to)

Build Your Own Ubuntu Repository with Docker

Build Your Own Ubuntu Repository with Docker 📦

Installing NVIDIA Container Toolkit

Docker Compose Playground

Docker Playground Manager 🐳

What’s New? ✨

Get Started 🚀

Advanced Docker Compose Guide with Examples

Advanced Docker Compose Guide with Practical Examples

Table of Contents

Introduction

SD Card Backup and Restore

GPG Bash Playground

GPG Bash Playground Guide

Introduction

Linux Boot Repair (Debian/Ubuntu)

Linux Boot Repair Guide (Debian/Ubuntu)

Introduction

Prerequisites

Critical Warning: Verify Partitions Before Formatting

Linux Boot Repair

UEFI Boot Repair

Windows Boot Repair

Windows Boot Repair Guide

Introduction

Prerequisites

Critical Warning: Verify Partitions Before Formatting

Windows Boot Repair

UEFI Boot Repair

Docker and Docker Compose

Docker and Docker Compose Guide

Introduction

What is Docker?

Git

Git and Gitflow Guide

Introduction

What is Git?

Linux Sysadmin Commands Guide

Linux Sysadmin Commands Guide

Introduction

Prerequisites

System Information

Hardware and System Overview

System Uptime and Load

User and Group Management

Managing Users

Managing Groups

Example: Creating a User with Specific Permissions

QEMU Disk Image and VM Management Guide

QEMU Disk Image and VM Management Guide

Introduction

Prerequisites

SSH Forward Tunneling

SSH Forward Tunneling Guide

Introduction

Uncomplicated Firewall

Ubuntu UFW Firewall Guide

Introduction

What is UFW?

Essential Bash Commands - File Management and System Analysis

Basic Docker Compose Guide for Beginners (Debian/Ubuntu)

Basic Docker Compose Guide for Beginners (Debian/Ubuntu)

Introduction

Windows System Repair and Maintenance

Chroot Guide for Debian/Ubuntu

Chroot Guide for Debian/Ubuntu

Introduction

LUKS Encrypted Container

ZFS Pool Management Guide (Debian/Ubuntu)

ZFS Pool Management Guide (Debian/Ubuntu)

Introduction