Today's update will be later, you may ask why, it's because my gastroenteritis has flared up again, I feel like I definitely won't live to 65.

The update will probably be at one or two in the morning, just refresh this chapter later.

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Abstract: With the progress and development of technology, more and more network users are using the computer network for a large amount of data operations or important information storage. Computer network security is gaining more attention, among which the application of firewall technology has become one of the most direct and effective important protective measures. This article, based on the analysis of basic concepts, elaborates on the types and functions of firewall technology, and then summarizes some existing security risks in computer network security. Finally, it illustrates the specific applications of firewall technology in computer network information security.

Keywords: Firewall Technology; Computer Network Security; Application

1 Related Concept Analysis

1.1 Firewall Technology

Modern firewall technology mainly targets a multi-component combination from the perspective of network security, which is a fundamental component of computer network security technology and one of the more common computer network security protection technologies. With the changes and development of computer network forms, especially the great development opportunities brought by wireless communication technology to computer networks, it also poses greater challenges to computer network security. Therefore, to ensure that computer networks can operate smoothly and securely, firewall technology is the most commonly used protection technology at the grassroots level of security defense. Firewall technology can promptly prevent malicious network invasions and protect against virus threats. For example, when a user downloads a file from the network, it's easy to enter a background operation that is persuasive or harmful to user information. The firewall can achieve timely reminders, warnings, or blocking access, thereby ensuring computer network security.

1.2 Computer Network Security

Computer network security is a relatively broad concept, which can be understood as protecting the software and hardware existing on the network during operation and management from illegal means of harm on the network. Computer network security can generally be grasped from two aspects: one is the physical layer of computer network security. The physical layer mainly refers to preventing the physical equipment of the computer or network physical equipment from being damaged by external forces leading to network information damage or loss. The other is the logical layer of computer network security. The logical layer mainly focuses on software maintenance, preventing data information from being damaged or lost through illegal network technical means.

2 Types and Functions of Firewall Technology

2.1 Types of Firewall Technology

2.1.1 Packet Filtering Firewall. A packet filtering firewall mainly exists at the bridging process between the network layer and the transport layer in the network, also known as a network-level firewall. The packet filtering firewall mainly concerns whether the network address to be accessed is the source address and identifies foreign URLs or ports that have been wrapped or tampered with, which might be harmful. As a network-level firewall, its working principle is through setting filtering rules for network data packets and then strictly comparing and verifying data packets from the network source according to the set rules, thereby making a decision to allow or deny access. 2.1.2 Proxy Service Firewall. A proxy service firewall is equivalent to adding another layer of protection to the internal computer network. The proxy service firewall mainly controls and audits the internal and external access of the network, and at the same time, logs the access information of users within the firewall. In the computer network, a proxy firewall mainly operates in the form of address transfer. External users can only see the proxy server when conducting network access, thereby terminating access without continuing to reach protected internal resources or data. Internal users have relatively free access to external resources, which can be achieved through address transfer. For computer network security, this is undoubtedly a means of protection. Therefore, from the perspective of its working principle and effect, the protective capability of the proxy service firewall surpasses that of the previously mentioned packet filtering firewall. 2.1.3 State Detection Firewall. A state detection firewall integrates all the features of the packet filtering firewall and proxy service firewall, serving as an enhanced firewall technology. The state detection firewall exists at the network layer, transport layer, and application layer of computer networks. Like the functionality achieved by the packet filtering firewall, a state detection firewall can filter and detect the network transmission data through IP, port, etc. At the same time, it implements functionality similar to a proxy service firewall at the application layer. In addition to comparing the network transmission data packets with the set verification rules, it also processes all data passing through the firewall as important data, thus further protecting computer network security and preventing data information from leaking or being illegally damaged.

2.2 Functions of Firewall Technology

2.2.1 Prevent Information Leakage. With the advancement of technology, people's communication methods and data transmission methods have greatly developed. Especially after entering the big data era, more and more personal information, enterprise information, and confidential data information are inundated into computer networks or stored in cloud space through computer networks. In this process, it brings great convenience to people's production, life, work, and management, but at the same time poses greater challenges to computer network security. Therefore, in computer network security management, firewall technology acts as a barrier to protect data information, providing a strong guarantee for computer network security. With the widespread use of computers, especially in recent years with the development of mobile communication technology and the widespread application of mobile application devices and software, how to prevent a large amount of personal data and private information from being leaked or illegally stolen is where the role of firewall technology in computer network security protection gets highlighted. 2.2.2 Purify Cyberspace Environment. With the use of computers and a large number of mobile devices, people's coupling degree with computer networks is increasingly high. There are also more risks of maliciously obtaining personal information or data from computer network users. Especially, many persuasive malicious invasion websites or applications may appear, which are difficult for non-professional users to distinguish from their malice on the surface. Such techniques are prevalent in the current computer network environment and largely disrupt the current computer network environment. Applying targeted firewalls set for network purposes and corresponding targeted filtering settings in the computer network environment can greatly help users scientifically identify fake websites and persuasive malicious network attacks, thereby cleaning up the computer network environment. 2.2.3 Implement Monitoring of Network Conditions. With the increasing dependence of people's daily lives on computer networks, solely relying on passive network defenses to protect users' important data or private information is very inadequate. Therefore, using firewall technology in computer network security to conduct real-time detection of network behaviors or events during network transmission processes can achieve proactive defense, thereby maximizing the protection of personal information and private data of computer network users in a complex and chaotic network environment. By using network firewalls, various behaviors during the network transmission process can be monitored, thereby making decisions to allow or deny access. This can greatly improve the security level of computer networks and can avoid or reduce the loss that data or information leakage might cause to users.

3 Existing Security Risks in Computer Network Security

3.1 Trojan Virus

The concept of the Trojan virus is not new; its rampage began with the widespread adoption of computers and the rapid development of computer networks. As technology advances, the Trojan virus increasingly exhibits higher concealment and destructive characteristics. In computer network security, the Trojan virus is one of the significant security hazards, causing substantial inconveniences in people's daily life and work. At present, the Trojan virus primarily spreads through wired networks or wireless communications, producing destructive effects. In the Big Data Era, Trojan viruses in computer network security cannot be ignored.

3.2 Hacker Invasion

Using illegal technical means to acquire or destroy network users' private information or data is the main method of network invasion nowadays, also known as hacker invasion. In the Big Data Era, people often store large amounts of important data in the cloud using computer networks and cloud technology. It is common for hackers to target data in network transmission or storage for illegal acquisition purposes. In the process of cybersecurity protection, the illegal acquisition of data through hackers' technical means is the most concealed and anti-monitoring method, posing the greatest risk to computer network security.

3.3 Software Vulnerabilities

Today, there are more and more application software in computers or mobile application devices. Most of this software involves a lot of user information or user data. In today's software development market, developers often focus on powerful functions, high execution efficiency, and low memory usage, while neglecting data security issues during software usage or insufficient consideration. This leads to numerous software vulnerabilities in security protection, undoubtedly providing opportunities for those intending to acquire user information through illegal means. After obtaining user consent through inducement, they can maliciously acquire or manipulate user data or information, causing certain losses to users. One important reason these software vulnerabilities can be exploited is due to the generally low firewall levels of users.

4 Specific Application of Firewall Technology in Computer Network Information Security

4.1 Firewall Encryption Technology

Firewall encryption technology is an important countermeasure for protecting against external intrusion. When external invaders use programs or data packets to invade network storage or transmission information, they typically log into the network via IP. Therefore, with the application of network firewall technology, upon receiving IP login information, it triggers an automatic request for identity verification information. Only upon successful verification of user information can login be permitted. However, the information after login will be forwarded to network administrators for acknowledgment. If user information verification fails, login will be denied, promptly triggering the network security warning system to report the intrusion situation, while tracking and protecting various behaviors of illegal users within the network environment. Hence, using firewall technology in computer network security can significantly prevent external malicious data intrusion, ensuring the safety of computer network users' information and enhancing the security coefficient of computer networks.

4.2 Firewall Repair Technology

In the Big Data Era, more and more information and data are flooding into computer networks, with various operations performed through computer networks. For users, not all data information is valid, and information management is not as categorized and handled as professional technicians. This inevitably leads to the emergence of a large amount of junk information, giving malicious invaders the possibility to invade using junk information to confuse. By utilizing firewall repair technology, through network monitoring methods, all acquired data information is classified and tabled based on users' specific needs, filtering junk information, and implementing appropriate interception or deletion processing according to settings. In this way, it prevents computer network invasion while saving computer storage space and improving the efficiency of user computer network access and data processing. The use of firewall repair technology enhances network monitoring effects, timely monitoring and processing of potentially exploitable junk information, playing a very important role in creating a secure computer network environment.

4.3 Firewall Protection Technology

Firewall protection technology is mainly applied to counteract the damage of the Trojan virus prevalent in computer networks. The Trojan virus is rapidly developing as a method of network invasion due to the increasing frequency of computer network usage each year. When users access web pages or retrieve or operate data stored in network databases via computers, they might fall victim to Trojan viruses hidden in websites or certain applications. Therefore, when users browse websites or perform network data operations, the firewall remains active, promptly identifying suspicious data malicious invasion activities, thereby intercepting and denying access. This ensures data security for users while also filtering out some useless junk information, enhancing the user experience. The firewall enabled in this type of network access primarily adopts a network proxy firewall, where IP filtering is accompanied by rule verification of data packets, thereby strengthening computer network security.

4.4 Firewall Protocol Technology

Firewall protocol technology is very similar to the transformation container control theory; it involves setting the size of data to be transmitted on the network precisely to the byte level at the beginning of data transmission within the firewall.