What is a Firewall?

• A Firewall is simply a program or hardware device that filters the information coming through the internet connection into your private network or computer system.

What is an application firewall?

An application firewall is a special firewall that is specifically coded for the type of traffic it is inspecting. The most widely developed application firewall is the web application firewall.

What is the difference between a host-based firewall and a network-based firewall?

A host-based firewall is installed on an individual computer to protect it from activity occurring on its network. The policy may affect what traffic the computer accepts from the Internet, from the local network, or even from itself.

A network-based firewall is implemented at a specified point in the network path and protects all computers on the “internal” side of the firewall from all computers on the “external” side of the firewall.

Network-based firewalls may be installed at the perimeter, or edge, of a network to protect a corporation from hosts on the Internet, or internally to protect one segment of the community from another, such as separating corporate and residential systems, or research systems from marketing systems. A network-based firewall cannot protect one computer from another on the same network, or any computer from itself

A web application firewall is less concerned with source and destination addresses, and focuses on the actual data in the packet to see if the requests being sent to a web server, and the replies issued from the web server, meet its rules.

For example, a web application firewall may have a rule that says a requested URL may not be more than 256 characters long. When a packet is found that has a longer URL in the request field it can be dropped without giving it to the web server.

Hardware firewall vs Software firewall

Hardware firewalls

Hardware firewalls are integrated into the router that sits between a co mputer and the Internet. They typically use packet filtering, which means they scan packet headers to determine their source, origin, destination addresses and check with the existing user defined rules to make an allow/deny decision.

Key advantages of hardware firewall.

1. Speed: Hardware firewalls are tailored for faster response times, so it can handle more traffic loads.

2. Security: A firewall with its own operating system is less prone for attacks. This in turn reduces the security risk and in addition, hardware firewalls have enhanced security

controls.

3. No Interference: Since the hardware firewall is an isolated network component, it can

be managed better, and does not load or slowdown other applications. The firewall can be moved, shutdown, or reconfigured with minimal interference to the network.

Software firewall

Software firewalls are installed on individual servers. They intercept each connection request and then determine whether the request is valid or not. Software firewall process all requests by using the server resources. Apart from performance limitation, the software firewall has numerous advantages.