Know your Computer's internet security

You may know that a computer can communicate with other computer only through the ports. A computer can be connected to the internet only through the ports. A computer has thousands of ports. But we require only a fewer ports. If a remote computer needs a port, it sends request to the computer for accessing a particular port. Each port is identified by its port number. The computer receives the request and allows the program in the remote computer to access the computer. This is the normal case. I mean the ideal case. But the programs in the remote computer are human created and so there is a chance for the presence of the error. Moreover some programs are malware that uses the trusted programs to get in to the computer. By closing the unnecessary ports we can prevent the remote computer from accessing our computer up to a limit. But this will not protect your computer completely from the attacks through the internet. This only reduces the chance of attack through the internet connection. For knowing which ports are opened and which are closed visit: http://scan.sygate.com/
If you use a firewall software you can manage the programs from accessing the internet. You can block the unwanted programs from accessing the internet. But the presence of rootkits can even cheat the firewall