Users want to attach computers to the Internet and receive emails, instant messages; browse web pages, download music and fun software etc. The problem is that this puts not just millions but billions of people at their doorstep! Imagine that if billions of people could reach a home instantly – how many ill intentioned people would come by to see if the doors and windows were secured? How many con artists would knock on the door? An Internet connected computer is in just that predicament.

When a computer is connected to a network by design it starts listening for communications from the outside world. Things known as ports get created which are special “doors” to the computer. These doors are special because they each have a designated program that will answer the door if it is knocked on. Examples of programs that listen for traffic from the network include:

1. instant messaging programs
2. Internet phone software
3. software for connecting to the computer from remote locations
4. Internet games

Even the operating system itself opens ports to share files or a printer or anything else on the computer. Each of those programs creates a “door” to a computer that it will answer if someone “knocks” on it. If that program is poorly designed then when it answers the “knocking” program could take advantage of it and thus compromise the computer.

In addition to people being able to come across the Internet and knock on one of the “doors” mentioned above – by using a web browser and surfing the Internet users are inviting people to access their computers. Every time a web site is browsed the web browser is downloading files to the computer and processing them. If that web browser is not programmed properly it is a huge security risk. For example on December 12 of 2008 Microsoft reported a big security hole in all versions of its Internet Explorer browser. The hole permitted data stealing software to be installed on the victim’s computer just by browsing an infected web page! Other examples of programs that invite access to your computer:

• Email programs
• File sharing and music sharing programs (by far one of the largest security risks)
• Instant messaging software

So aside from isolating a computer from the outside world, how can one protect a computer system? Here are some tips:

1. Don’t use Internet Explorer as your main browser. I am not bashing Microsoft or Internet Explorer particularly and something should be made clear: It is not necessarily that other browsers are programmed so much better but that 80% of people surfing the Internet are using Internet Explorer. Thus thieves interested in gaining access to the maximum amount of victims are going to spend most of their efforts exploiting the security holes of the browser that 80% of the people are using.
2. Put a firewall between your internal network and the Internet. A firewall’s job is to keep out those billions of people who can be at your doorstep instantaneously. It will only allow those you invite to knock on your computer’s door.
3. Use a Firewall on each individual computer. The network firewall mentioned above is a big step toward protecting the internal network. The problem is that it generally won’t protect users from themselves. A user browsing a website is telling the network firewall that it has given an invitation to that website and to permit files from that site to come through. If the user browses an infected website with a browser that has a security hole a virus will get into the network. If it is a certain type of virus it could start replicating itself within the local network. A computer firewall defends against this sort of problem.
4. Update your operating system and browsers. Security holes are constantly found in all operating systems and all browsers. Software updates patch these holes.
5. Use a good and up-to-date antivirus and spyware program. These programs help prevent damage from viruses that do make it to your system.
6. Backup your data. Short of isolating a computer it is impossible to 100% secure a system. If you backup your data then should the worst occur having good backups will prevent disaster.

The above represents the basics and go a long way to protecting computer systems.

security you may picture 2 security guards watching your personal computer. Basically PC network security is the defensive position that stops interlopers from getting access to your PC or network. Detection provides info when someone attempts to access your systems, whether they were successful and understanding what they might have done. Information stored on your computers include banking details, card recommendations and communication logs either discuss or email.

You can live with somebody reading you personal chats though not when they steal your bank or card info.

Trespassers frequently use other PCs as a method to launch attacks and disguise themselves as the intruded PC. Custom Malicious software is one of the largest network security issues facing the web. Centered attacks, engineered to be used against a single target, can avoid signature detection. Since the Spyware is custom-designed to avoid any known signatures and hasn’t ever been widely released, a signature for it won’t exist and no signature detection mechanism will find it, whether in anti virus software, intrusion detection software, or any other form.

Spyware may also be camouflaged from signature detection by utilizing polymorphic tools that change the code continually, creating a novel version with a completely unique signature everytime the programme is made. Suspect 2 people that have information stored on some media, say hard drives.If the 2 people need to share this information with one another, what will they do? This question is the basis that the networking principle is built. The 2 people can send the info to one another by duplicating it to cartable drive say flash memory and giving it to one another.

This is well if it won’t be happening steadily. But what if the 2 folks need to send info each day or maybe each hour? It’ll be hard to send it to one another particularly if they remote from one another. The concept of networking has been arisen from such cases. Rather than sending information between several folk on portable devices like floppy disks, they can easily connect their PCs to one another. Each person who would like to transfer the information to his buddy can simply transfer it through the network. So how does the information be transferred across the network? By connecting PCs of different folks to one another by wires the info can be simply broadcast.

Therefore the media will be wires instead of transportable devices though it can be also wireless machine. The wireless device will send the info in air by electromagnetic waves.

It is going to be electric beats if the info is broadcast on wires. In reality networks can be employed not only to share info but in addition to share devices like printers and CD-ROM. One user on a floor can utilize a printer that’s attached to another PC on anther floor by the network. The same is true for CD-ROM. This has got to be configured on both PCs by the operating software. This advantage of networking makes it beneficial for folks to use remote devices on their office.

Also it reduced the price tag because on printer or one CD-ROM is employed for all members of the network. Principally the network will be made of a set of PCs and a printer. This set of PCs will be answerable for sending the info to one another. One PC also may use the printer to print documents.If the network looked like this, it’s going to be called P2P. In this project, all PCs are the same and have equivalent processing power. The info is also distributed across them similarly. There is not any device which has more information in its hard drive. From another perspective, if there’s at least one PC in the network which has more stored information and more processing power and speed, then the scheme will be called server-based networking.

The PC which has the more data storage and the higher processing power will be called the server. This plan can be outlined also as a client-server based model as the other PCs in the network that have ordinary processing power will b treated as clients which will request information from the server. The web is build over this suggestion where the home PCs are the clients and the PCs that serve them are called servers. The most well liked server type is the website server which forwards page to the clients in the home or offices.