There are many ways to protect your network from unwanted connections. For example, a server firewall can help you protect your data from attacks on your server. It looks at packets of data to decide where to allow access and where to drop them. It may also use Stateful inspection to determine the origin and destination of a packet. First, here are some examples of how a firewall works. Then, here are some more examples. Hopefully, they will help you understand how a server firewall works.
Application Layer Filtering
While all servers need a firewall to protect against network attacks, some can be more secure than others. Application layer filtering enables server firewalls to protect networks against threats better. This method consists of two main parts: application layer filtering and protocol access. Application layer filtering blocks malicious traffic based on application and protocol characteristics. Application layer filtering requires additional processing power and, therefore, more powerful firewalls. However, this type of security comes with a high price. A server firewall with quad-core CPUs can handle these tasks and is highly recommended for securing networks and web services.
The main benefit of application layer filtering is improving security and performance. The main weakness of this type of firewall is that it cannot filter all kinds of traffic. If an attacker gets access to an insecure device, they can attach every machine on the network. Furthermore, some application-layer firewalls require client-side software to filter traffic involving application-layer connections. This can limit scalability and create management challenges.
Stateful Inspection
Stateful inspection is a packet inspection method that ensures all inbound packets result from an outgoing request. This technique aims to prevent harmful containers from entering the computer. For example, when you click a link on a website, an HTTP request is sent to the URL. All the packets that return would pass stateful inspection. Another example is an email program that periodically queries a mail server.
The Stateful Inspection method is one of the most effective ways to protect your server against unwanted traffic. The technology allows the firewall to examine incoming and outgoing packets to determine whether they are allowed or denied. It also monitors all sessions and packages. The technology behind the technique depends on the communication protocol and firewall technology used. However, if you use a stateful inspection firewall, you can ensure that no malicious packets reach your server.
Circuit-Level Gateways
In server firewalls, circuit-level gateways can help to provide secure network access. They enable the user to browse the Internet without exposing sensitive data. They also help to protect against phishing and spam. Circuit-level gateways establish a connection between two TCP segments, one from the inner host and one from the outer host. They also maintain a table of connections, allowing them to check incoming network packets. Once the data is confirmed, the firewall will close the connection.
Circuit-level gateways are similar to packet filtering but do not analyze incoming data packets. While these methods are helpful in some instances, they are not as effective as a stateful firewall. Therefore, using circuit-level gateways in conjunction with other security measures is best. For example, a circuit-level firewall can help prevent hackers from compromising your network’s security by blocking malicious IP addresses.
User Permission Control
Managing user permissions is one of the most common tasks when using a server firewall. Several organizations require control over access to specific categories, which are typically different for each user group. For example, an organization may want to restrict the access of certain users to particular websites but allow others to visit other areas of the network without restrictions. User permission control is an essential feature of server firewalls that administrators can use to ensure that only those users with the appropriate permissions can access the network.
For this purpose, you can define the public zone and the internal network. In a work environment, selected incoming connections are accepted, while in an untrusted environment, all incoming connections are rejected. Typically, you choose one of these zones when installing a firewall, but you can also change it later. The default zone for the firewall is public, and you can change this setting to reflect your security needs.
