A Linux firewall serves as a gateway for a computer to communicate outside its local network. It filters the information that comes, whether it is allowed to enter or not. This firewall provides a Web interface for control and security by blocking IP addresses and networks. This is a strong and effective type of firewall built on Linux servers.
It detects unused and unwanted ports and is configured by the system administrator. The way it is configured will direct its rules for disabling or allowing packets into the system to ensure security from outside threats. It looks at the sources, destinations, and the states of packets and is not limited to a subnet. It can be used to handle firewall functions for multiple subnets and set different levels of access for each subnet.
Linux firewall is applied to a stateless environment; which means that previous requests made to the server about the same Web page do not need to be known. It looks at each packet as isolated, hence the stateless form.
If the local area network has users that only require Web access and emails, it can be considered a stateless environment.
A Linux firewall is appropriate if you are using the same IP address all the time through a cable modem or DSL line. It secures the computer because it acts as an email and Web server. This is the best pick for stateless conditions.
However, Linux has a type of firewall capability to allow a higher level of examination for session-based transactions. Operating at the kernel level can increase the system performance. Some examples of Linux- based firewalls are:
- Astaro Security Linux – This is a new solution for firewalls.
- Censornet – The Internet Management program for LAN.
- Sentry Firewall – This is an economical way to maintain IDS, firewall or server.
- POP3/IMAP – This is good for email servers.
In choosing your Linux firewall, you have to look into some technical considerations, such as the quantity of traffic to be processed and the program’s efficiency and expertise on traffic infection. A good firewall can really fend off attacks from outside and serve as the layer of protection for your system.