Networking can be defined as ``any set of interlinking lines resembling a net, a network of roads || an interconnected system, a network of alliances.'' (www.interhack.net, 21/08/2008). It is the same when it comes to computer networks as well. A computer network can be connected in many ways; the method is not our priority. The priority is to figure out the number of ways that we can connect the computers. So we can say that a computer network is an interconnected network of computers.

What is computer security? One might ask. Computer security is preventing unauthorized users from gaining access to your computer system. Preventing accesses is one part of a security system. A good security system should be able to detect and warn or take necessary action against the intrusion. Preventing stops other parties from hacking into your system. The system should be able to block viruses and worm attacks as well. Detection helps to identify if any intrusion has been attempted and if so whether they were successful or not.

The security system should be strong enough to identify outside interference and inside interference. Outside interference is when a party who is not at all allowed to access the system tries to break into it. These intruders are mostly called hackers, crackers or attackers. Inside interference is when some one with access to the system tries to access parts of the system which has been blocked from the use of the relevant user. These are the tough ones to prevent and detect. The reason being the intruder is already inside the system. If the intruder is smart enough he/she will be able get through the defenses much easily than a person who is trying to access your network or system from the out side.

If you are using a small network you might think that it is not necessary to have a strong security system. Hackers do try and get into any network or even stand alone PC's. The reason is because hackers tend to use small networks and stand alone PC's to hack into other major networks like government or financial systems. Hackers tend to launch there attack through other systems so that they can hide behind several other systems and small networks. This makes it very difficult to track down the origin of the attack. Ones the intruder hacks in they will be able to watch all your actions on the computer. They will be in total control of your system and you might not even know it. Once total control is gained the intruder will be able to what they want when they want. If the intruder gains access of the administrator's computer or the server computer, he/she will be able to control the entire computer network.

It is not that difficult to break into a computer or computer network, provided the intruder knows what he /she is doing. Intruders always discover vulnerabilities in the software. Intruders call these vulnerabilities "holes." The complex software will make it very difficult but it is not impossible to figure them out. When these holes are found software companies provides "patches." Once you download these patches the specific hole will be blocked. But the problem is that there can be more than one hole in a software system.

These are some of the reasons why having a solid security system is very important. A firewall and an anti-virus guard is a must when it comes to a computer network or a stand alone PC. Some big networks use back to back firewalls to make sure that the possibility of an intrusion is minimized. The fight against system intruders is an age old battle. As security experts come up with new and more effective ways to secure computer systems hackers come up with new ways to exploit them. The only chance any system has against such attacks is to have the best security systems that are available.