Firewall in a Networking System

Firewall in literal terms means a wall or partition designed to imbibe or prevent the spread of fire.

In networking, a firewall is a term used for a "barrier'' between a network of machines and users that operate under a common security policy and generally trust each other, and the outside world.

In recent years, firewalls have become enormously popular on the Internet. Let's understand why.

What is Firewall?

Firewall is a device that forms a barrier between a secure and an open environment when the latter environment is usually considered hostile, for example, the Internet. It acts as a system or combination of systems that enforces a boundary between more than one networks.

Access controls are common form of controls encountered in the boundary subsystem by restricting the use of system resources to authorized users, limiting the actions authorized users can take with these resources and ensuring that the users obtain only authentic system resources

How do firewalls work?

At their most basic, firewalls work like a filter between your computer/network and the Internet. You can program what you want to get out and what you want to get in. Everything else is not allowed. There are several different methods firewalls use to filter out information, and some are used in combination.

How many types of Firewalls are there?

There are basically 3 types of firewalls. Let's discuss each type in brief.

Packet filters.

Packet filtering is a firewall technique used to control network access by monitoring outgoing and incoming packets and allowing them to pass or halt based on the source and destination Internet Protocol (IP) addresses, protocols and ports.

Stateful inspection.

Stateful inspection, also known as dynamic packet filtering, is a firewall technology that monitors the state of active connections and uses this information to determine which network packets to allow through the firewall.

Proxy Firewall

Proxy firewalls are considered to be the most secure type of firewall because they prevent direct network contact with other systems. (Because a proxy firewall has its own IP address, an outside network connection will never receive packets from the sending network directly.)

Having the ability to examine the entire network packet, rather than just the network address and port number, also means that a proxy firewall will have extensive logging capabilities; a valuable resource for security administrators who are dealing with security incidents.

Well, that's all on Firewalls. We shall continue with Anti malware softwares in the next article, stay tuned for that.

And as always, if you have any doubts, queries or suggestions, please let me know. Just click on Ask questions from the left panel of your screen.

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