Tutorials »

  • Blocking kids from certain Web sites

    Blocking Web site access to overly curious users in an open environment poses policy and technical challenges. You can meet the challenge with simple tools and target the result to a selected audience.

  • PowerPoint from the gadget in your pocket

    Can you really deliver a PowerPoint presentation directly from an Apple iPod, RIM BlackBerry, or Palm Treo? The answer is "yes," and I'm going to tell you how to do it.

  • Preparing for disasters

    Thinking about disaster recovery, a year after Hurricane Katrina, and on the fifth anniversary of 9/11, it's a good idea to look at contingency planning, especially for the organizations that would need to operate during a disaster. This is a different issue than transferring operations to a remote site. There are various issues in operating in a disaster environment, usually starting with electrical power but also extending to employee concerns and the need for resupply.

  • Explaining WPA2

    Can you explain the differences between WPA and WPA2 and provide some information on the different features and functionality?

  • Top Ten Mistakes that Hurt Your Google Ranking

    We do a lot of work on our sites to ensure that our readers can find our content through search engines, particularly Google. Over the 10 years we've been publishing media Web sites we've successfully avoided pitfalls that could damage referrals from search engines. We've also made some significant mistakes - from which we've recovered! Consequently we thought we would share the experience we've gained by putting together our definitive top ten list of mistakes that can damage your referrals from Google (we'll let you guess which ones we were guilty of).

  • How to restrain a wild Wi-Fi signal

    Say you wanted to protect your Wi-Fi network from surrounding buildings. The most obvious way to do this would be to secure the devices on your network using the wireless security protocol of choice. A very effective, but more extreme, way to do this would be to secure the building itself by making it act as a Faraday cage, shielding the radio frequency waves used by Wi-Fi.

  • Linux primer for networkers: Using the sniffer

    A few years back, I used an old 486 running Red Hat Linux and tcpdump to easily diagnose a client's denial-of-service attack, illustrating the benefits of creating a powerful network analysis tool from "scrap" parts. There are plenty of tools to build a similar Windows-based network analyzer, but Linux can run on machines that can't efficiently run Windows.

  • 802.11T puts WLANs to the test

    Buyers of Wi-Fi equipment and systems must be assured that all products have the performance and stability to carry mission-critical applications and data. However, testing of Wi-Fi, or 802.11, devices and systems for performance and stability is a challenge for the industry because of the complexity of the 802.11 protocol. That is compounded by the inherent mobility of the wireless devices and the prevalence of radio frequency interference.

  • Technology delivers high data rates

    An emerging mobile broadband technology can deliver high-speed data services to workers wherever they are.

  • Everyday Linux gripes

    As you already know, if I have to sit down in front of a computer, I want it to be running the Gnome desktop on Linux. I've watched it mature from a downright ugly, needlessly complex playground for geeks, to an attractive, simple interface that holds its own against commercial alternatives. And yet, every day I still encounter rough edges that make me think there aren't nearly enough folks out there hacking away at this stuff. I'd like to watch.

  • Security technology targets the LAN

    Access-control lists, originally designed for routers to deny or admit packets entering a network from a WAN, have drawbacks in controlling a diverse group of users accessing LANs. ACLs have no knowledge of traffic-flow semantics or content, can't adjust access rights for individual users, and suffer scalability and performance limitations.

  • Biometric authentication

    In this computer-driven era, identity theft and the loss or disclosure of data and related intellectual property are growing problems. We each have multiple accounts and use multiple passwords on an ever-increasing number of computers and Web sites. Maintaining and managing access while protecting both the user's identity and the computer's data and systems has become increasingly difficult. Central to all security is the concept of authentication -- verifying that the user is who he claims to be.

  • Windows dressing

    The Windows graphical user interface (GUI) isn't quite as customisable as the open source desktops are. Microsoft makes Windows dressing less than straightforward by using a plethora of binary files, Registry entries and INI configuration files to determine the look and functionality of the XP GUI. But don't let that stop you: there are many ways to swap out that drab Redmond-designed interface for something more to your liking.

  • Explainer: Proposed standard simplifies VPLS

    Virtual Private LAN Service is an emerging technology that lets corporations and carriers segment voice, video and data traffic across a Multi-protocol Label Switching-based backbone network. For corporations, VPLS allows for multi-point VPNs that provide QoS for any traffic type. And carriers can use VPLS to build private IP segments for a corporation across a common MPLS backbone.

  • Coping with a DoS attack

    We keep hearing about Denial of Service attacks, and how they can bring large organisations to a standstill, yet do we really understand the full range of events that the term encompasses? What does make up a DoS (or distributed DoS) attack, how it is done, and what can you do to prevent it happening to you?

  • Using TCP Wrappers to restrict connections

    TCP Wrappers (formerly LOG_TCP) is one of the many security utilities written by Wietse Venema. It works by logging the client host name of incoming telnet, ftp, rsh, rlogin, finger etc. requests. The security options you can configure are: access control per host, domain and/or service, detection of host name spoofing or host address spoofing, and setting booby traps to implement an early-warning system.

  • Securing dynamic web pages

    This article highlights some of the specific security issues around the use of dynamic code environments, such as SSI, ASP and PHP, and what you can do to minimise the risks.

  • Security considerations when migrating from Unix to Linux

    The Linux server market is expected to grow by 35% from last year, according to research firm IDC. Many of these Linux systems are replacing Unix in corporations looking to reduce IT costs. However, at the same time, there are more attacks on Linux than ever before. So, if you're considering a migration from your Unix systems to Linux, it's important to keep security in mind.

  • Object storage ensures high scalability

    Fueled by the computational power of Linux clusters, data-intensive applications are pushing the limits of traditional storage architectures. Whether mapping the human genome, imaging the earth's substructure to find new energy reserves, or generating the latest blockbuster animated feature, these applications require extraordinary throughput.

  • How to interpret SAN worldwide names

    All devices on a storage area network need to be uniquely identifiable. This is to ensure that data transmission occurs between the correct source and target device across a SAN fabric or loop.

  • Economist survey foresees shift in IT service delivery

    63% of LOBs expected growth of third-party tech services, while increased spending on enterprise IT services is anticipated by 65% of CIOs

    EMC

    A global leader in enabling businesses to transform their operations and deliver IT as a service.