Proxy service firewall

The proxy service firewall is a system that can help protect your network security by filtering messages at the application layer, allowing and blocking only those transactions which are appropriate for a user, requiring the user to enter credentials, etc.
These use cases can provide security against a malicious hacker attacking a network with vulnerable applications or services. We strongly recommend these use cases.

Network Security 

Do you use an application or service firewall?
We have a great guide on installing software and using software firewalls which will hopefully provide you with some helpful information for how to do so.

Software Firewall: A Guide to Understanding Firewalls in the Linux Industry (PDF) by Srinivas Kumar Verma, Senior Network Architect, Drexel
A proxy firewall uses TCP/IP to allow traffic out of one host or IP address to other hosts on the network and vice versa. This allows for other applications or services to work without interference, as certain traffic is blocked or passed through.

Proxy firewalls can prevent a malicious attacker from gathering more information from other networked systems by taking actions such as moving traffic through a proxy that hides the originating IP address (visit this website to get all the details). For example, a large corporate network might use a proxy, providing the corporate system with the ability to connect to the Internet from its corporate network, only to discover that an application on another server or computer is acting strangely. In the above scenario, all the malicious activities that are taking place are blocked so that the corporate system cannot trace the source of the problems.

To install a proxy firewall on a Linux system, simply follow the instructions found on the Wikipedia Proxy Firewall article. Follow the process for installing Software Firewall in the Software Firewall section of the Linux Wiki, and then install the Proxy Firewall package using the Network Manager Control Panel.