In Microsoft's latest operating system, Windows XP, we will find many new features, one of which is not too compelling, the Internet Connection Firewall, then the new Dongdong in Windows XP What kind of protection can we play against our love machine? How should we use it? Please ask me to discuss it with you. The first thing to explain is what is a firewall. From the Xinhua Dictionary, we can find that the firewall is an obstacle built between buildings to prevent the fire from spreading. In the computer, the role of the firewall and the reality are not much different. It is a virtual obstacle created in your personal computer and the external Internet world. Of course, it is not to prevent the spread of fire, but to guard against hackers. With the development of Internet technology, the network has brought infinite convenience to people and many problems have arisen. The hacking problem is one of the significant problems. The attacks of hackers are basically started by pinging a host that can connect to an IP address. When this host is found, it is usually used by some specialized hacking software to perform port scanning to find the system's vulnerability and attack. Since we know that the hacking method is through the ping command, then as long as we don't respond to the ping command, the hacker will think that the host can't connect and give up the attack. Microsoft certainly knows this, so the Internet connection in XP. The firewall of course does not respond to the Ping command, and it also prohibits external programs from port scanning the local machine and discarding all IP packets that are not requested. Therefore, it can protect our personal computer to a certain extent. However, after all, it only provides some basic means of preventing hackers, so it is not a substitute for some commercial personal firewalls, and it is not suitable for use in services. I have said so much, everyone must be tired of it, well, the following is a small series to enter the part of interest, how to set up an Internet connection firewall. Open the Start menu -> Network Neighborhood, (Figure 1) Click to view the network connection, (Figure 2) Select the local connection, right click (Figure 3) Click to view the network connection, (Figure 2) Click Advanced (Figure 4) Select Pass Protect or restrict my computer and network by restricting or blocking access to this computer from the Internet. At this time, the setting at the bottom right becomes optional. Click Settings (Figure 5) There are three main parts to the Internet connection firewall: The first part is the service item. By setting this section, you can let the firewall disable and allow which services. The second part is about the log. It can log all allowed and denied incoming packets so you can perform further analysis. The third part is about ICMP. My suggestion is to ban all ICMP responses. Check Protect my computer and network by restricting or blocking access to this computer from the Internet. At this time, the setting at the bottom right becomes optional. (Figure 6) But in the LAN should try not to use the Internet connection firewall, because it will affect some network applications. For example, access the shared folder and use the voice function of OICQ. Solving such problems is also very simple. One is of course to cancel the firewall, but this is not the recommended method. Another way is to find out which port OICQ uses to implement the voice function. Add a custom setting in the properties → Advanced → Settings → Service described above to make the firewall ignore the detection of this port. In this way, OICQ's voice function can be used normally. Well, we have already introduced the use of the firewall. It should be noted that it does not completely replace some commercial firewall software. However, for personal computer users who dial-up, it can really protect itself. The important thing is that it is free and basically does not occupy any system resources.