Digital Duct Tape I've had enough system administration jobs to know that companies tend to take drastically different approaches to how they handle technology.

For Linux users, the command line is a celebrated part of our entire experience. Unlike other popular operating systems, where the command line is a scary proposition for all but the most experienced veterans, in the Linux community, command-line use is encouraged.

I was proudly wearing one of my Salt Stack shirts the other day when my daughter asked me, "What is Salt Stack?" I began by explaining the problem it solved. If you have multiple servers and want to do things to those servers, you would need to log in to each one and do those things one at a time on each one. They could be fairly simple tasks like restarting them or checking how long they have been running. Or, you might want to do more complicated things like installing software and then configuring that software based upon your own specific criteria. You also might want to add users and configure permissions for them.

Every year for our Readers' Choice survey, the venerable tool rsync gets votes for favorite backup tool. That never surprises us, because every time I need to copy a group of files and folders, rsync is the tool I use by default.

Have you ever heard the following? "Welcome to the team! Here's a list of 15 applications to install, the instructions are in the team room, somewhere.

If you're the type of person who installs Ubuntu's server edition, you're also likely the sort of person who knows how to configure network settings. For most distributions, especially those based on Debian, the process is a bit strange, but familiar.

Who's using up all the bandwidth, and what are they doing? Use iftop to find out.

I am an impulse domain buyer. I tend to purchase silly names for simple sites that only serve the purpose of an inside joke. The thing about impulse-buying a domain is that DNS propagation generally takes a day or so, and setting up a Web site with a virtual hostname can be delayed while you wait for your Web site address to go "live".

As someone who's been working as a system administrator for a number of years, it's easy to take tools for granted that I've used for a long time and assume everyone has heard of them.

Puppet has provided baked-in Nagios support for a long time now. When combined with Exported Resources, Puppet is well suited to manage an intelligent Nagios configuration where nodes are automatically inventoried and monitored.

System administrators at the USENIX LISA 2011 conference (LISA is a great system administration conference, by the way) in Boston in December got to hear Michael Perrone's presentation "What Is Watson?"

Do you ever have that moment when someone asks you for a recommendation on a book, and when put on the spot you spin around in your office chair, scan your ever-growing library of books that you bought over the years of IT experience but either: A. Never read? B. Flipped through but never finished? C.Passed out halfway through the first chapter? 

Ever wonder exactly how vulnerable your network is? Using these tools can give you an idea and provide the means to protect yourself.

A high-availability stack serves one purpose: through a redundant setup of two or more nodes, ensure service availability and recover services automatically in case of a problem. Florian Haas explores Pacemaker, the state-of-the-art high-availability stack on Linux.

Directory services is one of the most interesting and crucial parts of computing today. They provide our account management, basic authentication, address books and a back-end repository for the configuration of many other important applications.

Sometimes events and equipment conspire against you and your team to cause a problem. Occasionally, however, it's lack of understanding or foresight that can turn around and bite you. Unfortunately, this is a tale of where we failed to spot all the possible things that might go wrong.

Poorly implemented monitoring systems can drive an administrator crazy. At best, they are distracting. At worst, they'll keep whoever is on pager duty up for nights at a time. This article discusses the best practices for designing systems that will keep your systems up and stay quiet when nothing is wrong.

"If we see light at the end of the tunnel, it is the light of the oncoming train" ~ Robert Lowell. Oh yes, another good quote. This post is on SSH tunneling, or as I like to call it 'Poor Man's VPN'. Contrary to the sysadmin's popular belief, SSH tunneling actually can be very valuable use for both techies and home users.

iptables is the user-space tool for configuring firewall rules in the Linux kernel. It is actually a part of the larger netfilter framework. Perhaps because iptables is the most visible part of the netfilter framework, the framework is commonly referred to collectively as iptables. iptables has been the Linux firewall solution since the 2.4 kernel.

Packet capture is one of the most fundamental and powerful ways to do network analysis. You can learn virtually anything about what is going on within a network by intercepting and examining the raw data that crosses it. Modern network analysis tools are able to capture, interpret and describe this network traffic in a human-friendly manner.