Andrew Hale: IT Talk & Other Topics

As much as I enjoy my iOS devices, I'll always have a soft spot in my heart for Palm, specifically WebOS. My first smartphone was a Palm Centro. The Centro was a blocky, modern redesign of what was essentially a Treo 650 and it ran Palm's aging PalmOS operating system. I chose the Palm over the Blackberry Curve and Motorola Q (running Windows Mobile), because PalmOS was more "hackable". When Palm changed the game, I fell in love with the Pre, and their new WebOS. I was originally going to write a quick bit tossing in my $0.02 about the ever-raging Android vs iOS debate, but writing a mobile phone history lesson seems like a more productive use of my time. Some trademark features of WebOS live on in current iterations of iOS and Android so I'll talk about those afterwards.

If you hate math, you're gonna have a bad time: I'll let you know that right now. You might not have noticed but you've used RSA encryption before. It gets it's name from the MIT scientists Rivest, Shamir, and Adelman who invented the algorithm. Let's take a look at how RSA encryption works.

As mentioned before, I'm setting up a LAMP stack using Cent OS v7 on my Raspberry Pi 3. LAMP stands for Linux, Apache, MySQL and PHP. The A for Apache could also be E for Nginx (pronounced like Engine-Ecks) and the P for PHP could also be P for Perl or Python. This software together forms what's referred to as a "stack", which is simply a common development term for a set of software that works together for a specific application. In this post, I'll be covering the installation and initial configuration of Apache, MySQL and PHP.

I could write several articles on using the Linux command line. However, while reinventing a wheel can be fun sometimes, my best sources that I've used have been the Command Line course on Code Academy , LinuxCommand.org , and the Unix Visual Quickstart Guide . Between those three sources and plenty of practice, you'll get the hang of it pretty quickly. Practice means breaking stuff and figuring out how to fix it. One of my college instructors once told us that Wisdom comes from Experience and Experience comes from Pain. Breaking stuff can be painful but it's only bad if you don't learn from the experience.

You, my one reader, may have noticed that my Quick Look posts come in bursts. The reason behind that is actually a simple one. I tend to get job interviews in bursts. I'll go months without hearing anything from any of the gigs I apply to and then suddenly, I have 6 interviews in 2 weeks. Often in nearly all of my interviews, there's one thing that I get asked about and I bomb hard. I remember an interview a while back where I was grilled about SysPrep, a tool that I haven't had to use in my experience (except for once some months ago). During that same interview, I mentioned DFS without being an expert in it, which was a mistake. The interviewer promptly asked me to explain DFS and what I could do with it. It was bad. Also in that interview, I found out that I didn't understand the difference between replication and backups. That interview was the worst one, but even my best interviews will have one tech question that I'm not sure about.

You may not realize it but you've very likely used LDAP. If you've signed onto a computer at a business or a school/college campus within the last 30 years then you almost definitely have. LDAP stands for Lightweight Directory Access Protocol. It's an open standard being supported by companies such as Microsoft, Apple, IBM, etc. I've already described DNS as akin to a phonebook for the internet. However, LDAP is like a company-wide phonebook. LDAP is the protocol for a special database that's been designed to store attributes about users, services, etc.

SELinux stands for Security Enhanced Linux and was developed, in part, by the NSA. Eventually, SELinux was released under open-source license and has made it's way into a number of Linux distributions.

You know how after you've signed on to your workstation, you can open up your Outlook or Lync without having to sign into them? Or, you can pull up your company's intranet without having to sign your username and password again? That's something called single-sign-on (SSO) and it's made possible by Kerberos. Kerberos is a security protocol for authentication. According to Greek mythology, Kerberos was the three-headed dog that guarded the gates of Hades.

I touched on SSH configuration in my post about performing the initial configuration on my CentOS Pi . Aside from one tweak to the config file, there wasn't a lot to do. In this post, I'm going to dive a bit deeper into how SSH Keys work, how to set it up in your environment, and then I'll dive a bit deeper into locking down the SSH configuration.

I've recently gotten a Raspberry Pi 3 and I've installed the ARM build of CentOS v7 on it so that I can have a small server to play around with some web stuff. My experience in IT has been largely Windows Server focused (AD, Exchange, System Center, etc.), storage, virtualization, backups, etc. Not much Linux or development exposure. I'd like to learn more about that area of IT, so I picked up a Pi and am creating an environment at home to learn more about Linux, Apache, PHP, MySQL and Git. In this post, I'm going to talk about the initial configuration of CentOS after you've installed it on your Pi.

I've had plenty of exposure to Linux over my years of working with computers but I have a confession: I've never used the Vi editor until recently. I bought a Raspberry Pi 3 to build a small Web-dev environment and reacquaint myself with Linux. I installed an ARM build of CentOS v7 on it and when I went to go through the initial configuration, I learned real quick that nano was not installed by default. Nano has always been my text editor of choice since the entirety of my Linux experience has been Ubuntu or Debian, (which is why I've installed CentOS). This isn't going to be a deep dive into Vi, just a basic intro to how to use it.

I have a particular interest in smart home technology. I live in an apartment currently so I don't have any "smart" devices deployed in my own home, but I follow the industry to see where things are going. As a bit of a smart home nerd, I was admittedly excited for the 2017 HGTV Smart Home special. However, I was disappointed.

The Raspberry Pi is awesome. If you're like me, you bought one to tool around with for educational purposes. You can run Kodi or gaming console emulators on it or you can combine some together for a tiny OpenStack cluster. At, $50-$60, they're easy on the wallet and running off of 5v USB power makes them pretty energy efficient. Sure, it's only a 1Ghz ARM processor which limits your OS choices but I'd rather have a Pi than running an old Dell PowerEdge or HP Proliant that I bought off of Craigslist. Instead of installing the usual Raspbian OS, this guide is on installing CentOS 7. However, the process described below is relatively universal to whatever OS you want to install on your Pi.

If you're in IT then you've likely heard of DNS. Most of us aren't experts in it but perhaps you'd like to know more about it. I'll go over a quick intro to how DNS works at a very high level and then wrap up with a description of the different types of records, or types of information, that comprise DNS.

I've been carrying a pen as part of my (mostly) every-day-carry, or EDC, for a couple years now. I bought the Zebra F-701 and after a few other pen purchases, the 701 is still my favorite of all. At first, I just wanted a pen that looked nice and for the moments I needed to sign something. I recall attending meetings when I worked at the university where the attendees were asked to sign-in on the attendance sheet: I tended to be the only one that didn't have a pen so I felt unprepared when I had to ask one of the other attendees if I could borrow theirs. Once I started college, I found myself using a pen much more often, so it had to be comfortable, relatively inexpensive (nice pens can cost hundreds of dollars), and still stylish enough to live in the pocket of a dress shirt.