In an age where internet connectivity is often an absolute necessity, businesses and household computers are often interconnected. This brings about benefits, but it also poses risks, particularly to security. Some of the risks involved when computers are networked are viruses and other malware spreading across local computers, hacking and intrusion from outside, and sensitive information being stolen by individuals with malicious intent.
Therefore, network administrators often find it necessary to install network security software to make sure that software and information are safe. There is no single software that can protect against all kinds of intrusions, and thus network administrators often use a suite of different software to handle these different threats. Here are a few examples of free network security software, and where to find them.
Intrusion detection. Network intrusion is among the more serious threats that a network can face. This is because there is often a malicious person behind these intrusions, and the intent is usually to gain access to sensitive information. One good example of a free intrusion detection software is Snort, which has versions available for Windows and Unix-based systems. Snort lets network administrators detect whether there are applications running on the network, or ports being opened with the intent of gaining access.
Packet sniffing. Another important aspect of network security is packet sniffing. This enables a network administrator to analyze what data goes through the network, which can involve malicious code, break-ins or other forms of risks. Packet sniffing is actually a tool that hackers also use to gain access to data moving around a network, but it can also be used proactively by network administrators. Some examples are Ethereal, which has been renamed into Wireshark. The software lets network administrators capture network traffic and re-build it, to see what kind of information is being sent, received and accessed.
Port scanning. Networks can often be broken into when there are open, unsecure ports running on the server. A port scan is a relatively quick way of detecting any open ports, which can then be closed or secured with a password. There are a handful of port scanners available for free download. Some examples include Shields Up! and LAN Spy.
Encryption. Network traffic is often sent and received in clear text. Therefore, anyone with physical access to your network (even if wireless) can sniff packets, and rebuild these on their computer, effectively being able to eavesdrop on conversations, and maybe even pick up passwords. Encryption ensures that data is securely sent and received, and that the sender's and receiver's identity are also secure. An example of free encryption software is PGP.
Antivirus. Lastly, a chain is only as strong as its weakest link. A network is only as secure as the weakest node or computer in it. Therefore, as a first line of defense, a network administrator should make sure that all computers that are connected to the network both physically and wirelessly should be running Antivirus software. There are dozens to choose from, which include both paid and free offerings. Some examples of free Antivirus software that are effective, lightweight and easy to use are AVG and Avast!. These software also offers automatic updates on a regular basis, so you can be sure your computers are secure even with viruses being created every day.
The best defense against malware and malicious intrusions is, of course, a well-informed user. As a network administrator, it is your responsibility to train users on how they should take care of their data and information. Responsible use of information and IT tools will help minimize these problems. However, using free tools to help protect the network against these risks would greatly aid in preventing any untoward incidents.