Common users use all aspects of the firewall

What is a firewall? Generally, the purpose of the application firewall is to restrict others from accessing the internal network, filter out insecure services and illegal users, prevent intruders from approaching your defense facilities, and restrict people to access special sites; it provides convenience for monitoring LAN security.
Personal firewalls generally have the following functions:

1. Data Packet Filtering

Ip Filtering or packet filtering is used to monitor and filter inbound and outbound Ip packets and reject suspicious packets.

In an information packet exchange network such as the Internet, all the information exchanged is divided into many information packets of a certain length, the header information includes the IP Source Address, IP destination address, and internal protocol (ICP, UDP, ICMP, or IP Tunnel), TCP/UDP destination port, ICMP Message Type, packet entry interface, and outbound interface. When these packets are sent to the Internet, the firewall will read the recipient's IP address and select a physical line to send it out. The information package may arrive at the destination through different routes, when all packages arrive, they are re-assembled and restored at the destination. The packet filtering firewall checks all IP addresses in the information package and filters information packets according to the filtering rules specified by the system administrator. If the firewall sets an IP address as dangerous, all information from this address will be blocked by the firewall.

2. firewall security rules

Security rules are the internal protocol settings for the LAN and Internet used by your computer, so as to achieve the best security of the system.

Security rules in personal firewall software can be divided into two types:

One is defined security rules.

Security rules are defined as several solutions, which are generally divided into low, medium, and high. In this way, users who do not understand network protocols can flexibly set different security solutions as needed. For example, ZoneAlarm firewall.

You can also customize security rules.

That is to say, when you are familiar with network protocols, you can set a protocol based on the security status you need.

3. Event diaries

This is a major function that every firewall software can't afford. It records all events that the firewall software monitors, such as the source, protocol, port, and time of intruders. The recorded events are determined by the functions of the firewall.

What is the best firewall? This is a frequently asked question by netizens.

I personally think that the firewall is not necessarily the best choice, because the Personal Firewall is mainly designed for the practicality of individual users. In addition to the above functions, it also integrates some tools, for example, tracking host name or IP address, detecting Trojan Horse, camouflage, and so on. Choose based on your own needs, and eliminate some simple firewalls in constant learning. I divide users into five types:

1. users who do not know the network protocol only want to visit the webpage. You can use a silly firewall. Example: Intrusion Detector, Intruder Alert 99

2. If you access the Internet to chat or frequently attacked users, you can use the ProtectX and LockDown2000 firewalls, which both have the IP tracking function. If you are under attack, you can immediately trace it.

3. Users who frequently encounter scans use Internet Firewall 2000, AnalogX, and NetAlert. These two firewalls can block or monitor your open ports.

4. For users accessing the Internet in a LAN, the firewall must support the NETBIOS setting function. For example, AtGuard, Zone Alarm, conseal pc firewall, Skynet firewall, and BlackICE.

5. Users who use network protocols freely. Norton Internet Security 2000 V2.0 Personal Firewall and AtGuard firewalls both have detailed custom network protocols.

The five user categories mentioned above do not have to be used according to such classification, but they have the features of that classification. For example, the Zone Alarm and Skynet firewalls provide security rule solutions for common users. users who do not know network protocols can also use them freely.