Here is a scenario you can think about. An administrator of a company has been accused of hoarding illegal material of questionable moral content on his company network system. You have been called upon to examine the suspect server and unearth evidence related to the said illegal material. Your boss has told you that you are not allowed to shutdown the server.

A project to protect national internet infrastructure in Estonia is planning to publish some of the tools it has developed as open source under the European Union Public Licence (EUPL). The project, run by the National Informatics Centre (RIA), is already using a number of open source tools in its goal to monitor Estonian network traffic and prevent network problems.

Ubuntu Forensic is the use of Ubuntu for digital forensic purposes. As it provides a wide range of forensic tools as well as anti-forensic and cracking tools, so it is reliable to investigate a computer crime and analyse digital evidence on it.

Network Security Toolkit is one of many live CD Linux distributions focusing on network monitoring, analysis, and security. NST was designed to give network security administrators easy access to a comprehensive set of open source network applications, many of which are among the top 100 security tools recommended by insecure.org.

Awareness of what's happening on your network, and why, makes the difference between average and excellent network administration. Great tools are needed to obtain this knowledge quickly and accurately. Fortunately, some of the best network monitoring tools are free. This article lists the top five.

Take a stroll through an AT&T store this holiday season and you can't help but notice that it's deja view all over again. Apple is making the same mistake with the iPhone that it made with the PC. Android phones come in all shapes, sizes, price points. Off in that lonely corner is the iPhone in two models: the latest iPhone 4 and the older iPhone 3GS. That's it.

When the city of Madera, Calif., needed a new voice system, it turned to open source technology -- not just for the IP telephony but for an entire network-infrastructure overhaul and loads of other functions. All the renovations cost less than half the estimated price of deploying a commercial VoIP system alone.

There are certain aspects to system administration that you can learn only from experience. Computer forensics (among other things the ability to piece together clues from a system to determine how an intruder broke in) can take years or even decades to master. If you have never conducted a forensics analysis on a computer, you might not even know exactly where to start.

Wireshark is a very versatile utility to monitor all the neighborhood network activity, including disassembling packets and viewing data transmitted from anyone who is connected on your LAN (or Wireless LAN). I'm using Wireshark to monitor the activity of the network, and I explained the packets transmitted between the peers.