Firewall alerts me to intrusion attempts

Hits:15

 Hackers today have many tools in their arsenal, and one of them is software that runs automatically and scans the Web for open, unprotected data ports. These port monitors (also known as port scanners), are constantly seeking computers with visible, high bandwidth and unprotected data ports. Unlike a hardware port, a data port in a computer represents the end of a logical connection between a sending computer and a receiving computer. It is not a physical destination, but rather a virtual receiving point for data transmitted through the Internet. Ports let your computer know which application (email, browser, FTP [File Transfer Protocol]) is the recipient of a data transmission. When you send an email message to a friend, your transmission is ultimately received into port 25, the data port designated for SMTP (Simple Mail Transfer Protocol) traffic.
 
 The TCP/IP (Transmission Control Protocol/Internet Protocol) allows for 65,536 possible data ports, so there are 65,536 possible doorways into your computer. Port scanner programs work automatically, scouring the Internet looking for vulnerable computers. In terms of ports, a vulnerable computer's data ports are visible and actively listening for transmissions to receive. When a good firewall is installed, your computer's ports are invisible to the outside world; they are undetected by a hacker's port-scanning tools. Your firewall's display of constant scanning activity is testimony to the fact that hackers are a busy lot, constantly looking for vulnerable computers to exploit.
 
 Not all traffic your firewall detects is hostile, however. Many times, ISPs (Internet service providers) send transmissions to your computer during the course of managing their networks. Your firewall may interpret a message from your ISP's system as hostile, even though it is harmless.