The Internet Storm Center has a post about how to get information from computers on the Internet.
So you want to use the Internet? If you want to use it, you have to be connected.
If you are connected you can be scanned.
Hackers will scan you until they find a vulnerability.
There are many types of ports udp and tcp are the ones to focus on.
In fact there can be 2^16 = 65,536 ports. (2 bytes of port info for each packet)
Your computer can theoretically have at least 131k ports.
So the hacker is scanning you for open or closed ports, what is the status of he port? Then once the status is found more is done. (Our Alpha Scan)
The hacker will keep working until they find a crack in your defenses.
Once the crack is found the attack really commences… (Sigma scan) and Omega scan as well – depends on our initial findings – or Alpha report