If an attacker knows that your server is listening on a given port, potentially ready to allow entrance, he can target it for a security breach. An open port can be seen as a door to your system, and a password would be its key. But what would happen if the door were hidden, invisible, and you needed to use something special to make it visible again? A technique called port knocking keeps ports closed until users provide a secret knock sequence that only then allows them access to your site.

In its 22 years of existence, the Vim editor has become the center of an ecosystem of plugins. Whether you are coding or writing a text document, you can probably find a plugin that will make you more productive.

You only need a basic command of Git to make the source code management utility incredibly useful. But Git offers a range of commands and options that can make your workflow run even more smoothly. Here are a few Git tips and tricks to make this tool even greater than you already thought it was.

If you want to ensure optimal performance from the GlassFish application server, you must monitor certain essential performance indicators. Here are some tips to help you keep GlassFish running trouble-free.

In my previous article, I shared a few tips to help you improve your general productivity with the Eclipse IDE. Another great productivity feature of Eclipse is its templates, which let you turn a brief snippet of code into a whole chunk. This is particularly useful when you're writing Java, with its tendency to use a certain amount of boilerplate code. Let's look at some examples of built-in templates, and see how to write your own.

If you code in Java, chances are you've used the Eclipse integrated development environment. If you're not a Java coder, you may have used Eclipse for one of the several other languages it can support via plugins. Even so, you may not know all the tools that are available for the Eclipse power user that can rocket your productivity levels upward. Check out these tips on helpful keyboard shortcuts, setting up the editor, and navigating at speed through your code.

The instructions for installing GlassFish 3.1, the most recent version of the open source application server, are meant to be straightforward, but the universal Unix installation guide does not cover many Linux – and more specifically CentOS – aspects that prove to be troublesome. Here are some tips for overcoming some of the most common GlassFish installation issues.

Databases tend to grow over time as they store more and more information. To ensure your database information can be accessed in the shortest time possible, you need to learn a few tricks to speed up data retrieval. For MySQL databases, you can use indexes and partitions to limit the amount of data that MySQL has to traverse to fetch query results, and use some other optimization tricks to further improve performance.

Almost every IT service relies on the Domain Name System; DNS failures cause problems with web access, email communication, applications, and even database operations. Under Linux, BIND is the most widely used DNS server. While common BIND administration tasks are simple and straightforward, BIND also has powerful and advanced features for improved DNS security and performance. Thus it pays to make some configuration changes to ensure a more robust corporate BIND implementation.

Apache remains the world's most popular web server, thanks in part to the abundance of powerful modules that work in synergy to extend the web server's core functionality. Here are some useful Apache modules that can improve your web server's performance, content delivery, and overall security.