Functions and roles of firewalls in networks

Functions and Roles of Firewalls in Networks

With the rapid advancement of computer network technology, the issue of network security has become increasingly prominent for all types of users. Based solely on the data I have access to, approximately 20% of internet users have been troubled by hackers. Despite the rampant activities of hackers, network security issues still haven't received sufficient attention; many users believe that network security problems are far from affecting them. This can be seen from the fact that more than 40% of users, especially enterprise-level users, do not have a firewall installed. All these issues point to one fact: most hacker intrusion incidents occur due to the failure to properly install firewalls.

The Concept and Role of Firewalls

Originally, the term "firewall" referred to the walls built between houses in ancient times, which prevented fires from spreading to other houses. However, the firewall discussed here is not a physical firewall but rather a defensive system isolating the local network from external networks. It's a general term for this category of preventive measures. In the context of the internet, firewalls are a very effective network security model. They isolate risk areas (i.e., the internet or networks with certain risks) from secure areas (local area networks) without hindering people's access to risky areas. Firewalls can monitor inbound and outbound network traffic, thereby accomplishing what seems like an impossible task: allowing only safe and authorized information to enter while resisting data that poses a threat to the enterprise. As errors and vulnerabilities in security become more common, attacks on networks may come not only from sophisticated attack methods but also from low-level configuration mistakes or inappropriate password choices. Therefore, the role of a firewall is to prevent unwanted and unauthorized communications from entering or leaving the protected network, compelling organizations to strengthen their own network security policies. Generally speaking, firewalls can achieve the following objectives: first, they can restrict others from accessing the internal network and filter out unsafe services and unauthorized users; second, they can prevent intruders from approaching your defense infrastructure; third, they can limit users' access to specific sites; fourth, they provide convenience for monitoring internet security. Since firewalls assume network boundaries and services, they are more suitable for relatively independent networks, such as intranets with relatively concentrated types of networks. Firewalls are becoming a very popular method for controlling access to network systems. In fact, among web sites on the internet, more than one-third are protected by some form of firewall, which is one of the strictest ways to guard against hackers and offers stronger security. Any critical servers are recommended to be placed behind a firewall.

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