Security Firewall installation for Internet access

Exposing a PC to the Internet is like leaving home without locking the door. The final result is that someone has intentionally or unintentionally broken into your room and swept away the gold and silver jewels. How can we ensure system security? Installing firewall software is the most commonly used measure. Generally, as a supplementary measure, installing a hardware-based firewall is also a common measure.

Even if you are an experienced veteran, it is not easy to configure the firewall. If you have abandoned the idea of installing a firewall, or are not sure whether the firewall has fully protected the system, it does not matter. Today we will resolve the secrets for you.

Open the Merriam-Webster dictionary. The original meaning of "Firewall" is: a wall used to block the spread of fire. In the information technology field, firewalls are used to prevent computers from being infiltrated by harmful Internet attacks. Unlike fire, threats from networks do not only affect computers that are close to each other. If someone exploits your IP address and TCP or UDP ports, no matter how far they are, your system will be hit.

Whenever you use a browser or email, or download files from an Internet site or remote server, data is transmitted through one or more ports in the system. And those computer hackers, whether they are the talented teenagers who snoop into the system, the hackers who seek to gain insight into the system, or the spam information popped up by the Windows XP Messenger Service, the attack policies are the same-that is, an open port that can enter the system is found, or you are spoofed to open such a port.

The firewall can monitor thousands of ports-whether dial-up connections or broadband networks-to block unauthorized access requests. Hardware-based firewalls are generally integrated into routers and gateways, which are located between PCs and Cable or DSL Modem. The Software Firewall runs on the PC.

For hardware firewalls, they are better at protecting PC networks connected through broadband. More importantly, they not only provide routing functions, but also act as a NAT (Network Address Translation, Net Address Translation) server that can hide the IP addresses of computers in the LAN from external visitors.

For this reason alone, the hardware firewall is enough to become a smart choice for broadband users, even if you only have one PC. In this case, you may want to buy a 4-port router like Linksys VEFSR41 or D-Link DI-704P, they are not high, about 300 ~ 400 yuan. Some products also have built-in wireless access modules, which may be slightly more expensive. You can query detailed information on the relevant websites.

Firewall selection policy

The hardware firewall is highly configurable: It can block all data outside the specified port. Therefore, planning and configuring the hardware firewall requires a lot of work. On the contrary, software firewalls run on your PC and are relatively easy to set up and maintain. In addition to blocking illegal access through open ports, software firewalls can also prevent malicious programs from sending data to remote servers, such as Trojans, spyware, and backdoor software compiled by teenagers ).

If you connect to the Internet through dialing, the external hardware firewall is not necessarily your best choice. The advantages of the software firewall in this respect are very obvious. For Windows XP users, it is risky to protect the PC by using the integrated ICF (Internet Connection Firewall, Internet Connection Firewall) in the system alone.

To enable ICF, right-click "start" * "Control Panel" * "network connection", right-click the Internet connection to be protected, and select "attribute" in the shortcut menu, go to the "advanced" tab and select "Protect my computer and network by limiting or blocking access from the Internet, click "OK" (1 ).

Although this will reduce the pressure on system security, it is far from enough. According to the above method, it is much safer than no firewall, but compared with other professional software firewalls, Windows XP built-in firewall can only monitor access connections. Therefore, such as Back Orifice, NetBus, or other backdoor programs, ICF is powerless for illegal access of this type.

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