Linux

Introduction

In previous articles, we explored different file transfer protocols — from classic FTP and SFTP to modern solutions like S3 and WebDAV. Now let’s take a closer look at Rsync — a powerful tool and protocol that stands out for its efficiency in synchronizing files and directories.

Rsync is perfect for backups, data synchronization, and automation tasks, thanks to its ability to transfer only the modified parts of files.

Introduction

When it comes to file sharing not over the internet, but within a local network (at the office or at home), other protocols take the stage. The two main competitors here are: SMB — the king of the Windows world, and NFS — the standard for Unix/Linux.

SMB (Server Message Block) — the language of Windows communication

SMB is a network protocol that provides shared access to files, printers, and other network resources. If you’ve ever opened a shared folder in Windows — you’ve used SMB.

Getting a new VPS is just the beginning. By default, the server is insecure and not ready for production use. This checklist will help you step by step to prepare your VPS: close security holes, enable updates, and configure the basic infrastructure.

1. First login and changing the root password

Connect to the server via SSH:

ssh root@YOUR_IP_ADDRESS

Change the temporary password to your own unique and complex one:

passwd

2. Create a new user with sudo

Working as root all the time is dangerous. Let’s create a regular user:

Introduction

Netplan is a utility for declarative network configuration in Linux (Ubuntu, Debian, and derivatives). It is usually used for simple cases like Ethernet or Wi-Fi, but it can do much more:

• tunnel interfaces (IPIP, GRE, VXLAN, WireGuard),
• VLAN,
• bridges,
• bonding (interface aggregation).

These features allow building complex network topologies — from home VPNs to data centers and cloud environments.

Tunnel interfaces

Tunnels encapsulate packets of one protocol into another. They are used for VPNs, inter-server connections, or network isolation.

Hello! If you’re even a little interested in the web, you’ve probably heard of curl. It’s a powerful and versatile command-line tool for interacting with web servers. It is used to send and receive data over various protocols: HTTP, FTP, SFTP, as well as mail protocols.

This guide is your first step. We’ll focus on the basics to help you understand how curl works and how to use it for everyday tasks.

Swap is virtual memory on disk that saves your VPS from crashing when RAM runs out. On low-cost servers, it’s an indispensable tool to avoid failures during short-term memory usage spikes. Setup is simple: create a file, enable it, and add it to autoload. But remember — it’s insurance, not a replacement for RAM.

Introduction

Modern VPSs are usually provisioned with enough RAM but often without swap (swap file or partition). This is a deliberate choice by providers who want you to quickly upgrade to a more expensive plan.

FreeIPA: The Untamed Titan of Enterprise Identity

Introduction

While Keycloak and FusionAuth focus on the web, FreeIPA operates on a different level. It’s not just an authentication server. It’s an integrated solution for identity management and security policies in UNIX/Linux environments. It’s not designed for quick web app integration but for building centralized access control at an enterprise scale. If your infrastructure consists of many Linux servers, this tool is your ally.

Introduction: From Reactive Defense to Proactive Security

In 2025, attacks on servers are becoming increasingly sophisticated, and reactive measures (firewall, Fail2Ban, CrowdSec) are no longer enough. The modern DevSecOps approach requires proactive hardening—strengthening the system—to minimize the attack surface before public exploits appear.

Lynis remains one of the key open-source security auditing tools for Unix systems, but today it is crucial to complement it with integration into security standards frameworks (CIS, SCAP) and automation in CI/CD pipelines.

Introduction: The First Line of Defense for Your Server

Before thinking about complex intrusion detection systems such as Fail2ban or CrowdSec, you need to build the first and most reliable line of defense—a firewall. A firewall controls all network traffic entering and leaving your server and blocks unauthorized connection attempts.

Traditionally, Linux servers have used iptables to manage firewalls, but its syntax can be complicated and confusing. Fortunately, there is a simpler and more intuitive tool — UFW (Uncomplicated Firewall).

What is Xen?

Xen is a powerful and flexible Type 1 open-source hypervisor that runs directly on server hardware, delivering high performance. Its unique architecture, based on the concept of paravirtualization, became the foundation for many major cloud platforms, including the early versions of Amazon Web Services (AWS). Xen is known for its performance, security, and ability to flexibly manage resources, making it a popular choice for building scalable and fault-tolerant environments.