A Firewall is a network security device that monitors incoming and outgoing network traffic and decides whether to allow or block specific traffic based on a defined set of security rules. Firewalls have been a first line of defence in network security for over 25 years. They establish a barrier between secured and controlled internal networks that can be trusted and untrusted outside networks, such as the Internet.

How do Firewalls protect Businesses ?

• Large corporations often have very complex firewalls in place to protect their extensive networks.
• On the outbound side, firewalls can be configured to prevent employees from sending certain types of emails or transmitting sensitive data outside of the network.
• On the inbound side, firewalls can be programmed to prevent access to certain websites (like social networking sites).
• Additionally, firewalls can prevent outside computers from accessing computers inside the network.
• A company might choose to designate a single computer on the network for file sharing and all other computers could be restricted.
• There is no limit to the variety of configurations that are possible when using firewalls.
• Extensive configurations typically need to be handle and maintained by highly trained IT specialists, however.
• There are two ways a Firewall can prevent this from happening. It can allow all traffic to pass through except data that meets a predetermined set of criteria, or it can prohibit all traffic unless it meets a predetermined set of criteria.