Security

How to Further Secure SSH With a Port-knocking Sequence on Ubuntu 18.04

Introduction Besides changing the default port for SSH, and using a key pair for authentication, port knocking can be used to further secure (or more accurately, obscure) your SSH server. It works by refusing connections to your SSH network port. This es...

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Port Forwarding and Proxying Using OpenSSH

Introduction SSH, also known as Secure Shell, can be used for much more than obtaining a remote shell. This article will demonstrate how SSH can be used for port forwarding and proxying. The only prerequisites are an OpenSSH server (installed by defaul...

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Let's Encrypt: Migrating From TLS-SNI-01

Let's Encrypt is a free service that generates certificates to secure your website. It supports generating different types of certificates, including single-domain and wildcard. In addition, it has numerous methods to authenticate your domain to generate ...

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Configure Ubuntu Firewall (UFW) on Ubuntu 18.04

Install UFW UFW is installed by default in Ubuntu 18.04, but you can verify this: which ufw You should receive the following output: /usr/sbin/ufw If you don't receive output, that means that UFW is not installed. You can install it yourself if thi...

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How to Test Your Firewall Configuration With Nmap on Linux

Introduction Nmap is a free and very popular network security scanner. It is easy to use and very powerful. This article will explain the installation and usage of Nmap for testing firewall configurations. Even though you can check which ports are open t...

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How to Setup Two-Factor Authentication (2FA) for SSH on Debian 9 Using Google Authenticator

There are several ways of logging into a server over SSH. Methods include password login, key-based login and two-factor authentication. Two-factor authentication is a much better type of protection. In the event that your computer gets compromised, the ...

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Setup Let's Encrypt With Nginx on Ubuntu 16.04

Let's Encrypt is a Certificate Authority (CA) that provides free SSL certificates with an automated client. By using a Let's Encrypt SSL certificate, you can encrypt traffic between your website and your visitors. The entire process is simple, and renewal...

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Install and Setup CentOS 7 to Remotely Unlock LVM on LUKS Disk Encryption Using SSH

LUKS (Linux Unified Key Setup) is one of the various disk encryption formats available for Linux that is platform agnostic. This tutorial will provide you with root and swap partitions inside of a LVM (Linux Volume Manager) volume contained inside of an e...

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How to Use Mosh on CentOS 7 for Remote Server Administration

Mosh, the abbreviation of "mobile shell", is a rising remote terminal application designed to provide better connectivity and user experience than SSH-based terminal applications. When talking about remote server administration technologies, SSH obviousl...

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Create an HTML 5 RDP/SSH Frontend Using Guacamole on Ubuntu 16.04 LTS

Introduction The goal of this tutorial is to get rid of the public SSH and public RDP connections. By placing this all behind a very convenient HTML5 client, we can add a layer of security for accessing our cloud. Guacamole also logs any remote access, ...

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