Fail2ban is an intrusion prevention software framework that protects computers from brute-force attacks. It scans log files and bans IP addresses that show malicious signs, such as, too many password failures. Fail2Ban then updates firewall rules to reject the IP addresses for a specified amount of time, although any arbitrary other action (e.g. sending an email) could also be configured.

Public key authentication is an alternative and more secure means of identifying yourself to a login server, instead of typing a password. It is more secure and more flexible, but more involved in its set-up. It can also be used to provide a password-less login experience when using SSH and it can authenticate the system your logging into, thereby assuring your not being spoofed.

This is a step-by-step guide of how to set up your Raspberry Pi as a "headless" computer, that is, access it via network connections without a keyboard or display. This is done by configuring the Raspberry Pi without needing any kind of monitor or keyboard attached. I go a little further by showing how to upgrade the firmware / OS / development tools, bootup without X Windows, setup password-less login, and establish some basic security.

Since I'm not using a static IP for my home router, my ISP can change my IP address as they sees fit. But in order for me to SSH into my home server from outside my local network, I need my home’s router current IP address. Here a create a simple utility that pushes to my cell phone the new address when my router's IP address changes.

I want to log into my home Linux box from my work laptop, which is a Mac. I also what to use all the tools I have grown comfortable, particularly vi/vim/gvim while on my home system. This requires X11 to work on the Mac. Here I show you how this is done on the Mac using XQuartz, Apple's version of the X server.

You might want to run one X Window System desktop environment on your local computer while accessing second computer, including its own desktop environment, using the first computer’s screen and keyboard. This is known as "X nesting". Open-source clients such as Xnest and Xephyr support X nesting.

This article reviews the kinds of maintenance activities required by Ubuntu / Debian / Raspberry Pi Linux distributions to keep them running as they should. It covers topics like OS and applications updates, disk / filesystems integrity, and cleaning up filesystem clutter.