The concept of a firewall is derived from the actual firewall, which is a fireproof wall used to prevent the spread of fire in buildings. A firewall in terms of computing refers to software programs or hardware programs located at the entry point of network systems to monitor incoming and outgoing traffic and protect the computer against unauthorized access including malicious programs and hackers. Their primary purpose is to keep the network secure since the internet is a very volatile environment with ever-present danger of hackers and malicious codes. These tools are especially important for corporate network systems that store very sensitive information. In this case, this institution may need to use multiple redundancy firewalls to ensure maximum security for their information. Hackers and creators of malicious programs are advancing rapidly, meaning that the firewalls have to become advanced as well so as not to be compromised. There are many firewalls in the market that are very advanced and that guarantee maximum security for your computer system.

How a Firewall Functions
Basically, a firewall for computer security performs three basic functions. These firewalls include packet filters, application level gateways and circuit relays. Each of them performs distinct tasks that contribute to the security of your computer system. Below is an explanation of each type of firewalls:

1. Packet Filters
Packet filtering is offered by the most basic firewalls. A packet is a given amount of data of a limited size, kept small to increase ease of handling. Internet traffic flows in form of data packets.

Packet filters only examine the protocols and address information of each data packet. Its relationship to other data packets and its content are not examined. This firewall doesn't know the source of such data and doesn't examine the applications on the host or local network.

These firewalls can be configured to allow or reject data packets depending on their IP address, their destination ports or according to their protocol. Packet filtering is a good form of security, but is not the absolute best. Its main downsides are that the address information can be falsified by the sender and data in a given packet may manipulate the computer system giving a loophole to hackers. It is upside is that it is very simple and easy to implement.

2. Circuit Relays
Circuit relays are also called circuit level gateways. This firewall provides additional security in the computer system. It uses the tactic of validating the network connections before allowing data to be exchanged. This type of firewalls not only allows or disallows data packets, but also ensure that the connection between both ends is valid according to the configured policies. If the connections are valid, it allows data from the allowed source for a limited duration according to its configuration.

The validity of a connection is determined by factors such as the destination IP address, source IP address, destination port, source port, time of day, user, protocol and the password. Once a connection is established, no further checking occurs.

3. Application Gateway
This firewall approach applies specific security measures to applications such as the FTP and Telnet servers. The application gateway acts on behalf of the servers and handles all the exchanges with your computer system.

It can allow or reject data depending on its configuration. For instance, it can allow some commands to servers but not others. However, this approach can cause a lapse in performance.

There are many firewalls that can carry out all the three basic tasks or each distinct tasks. Examples include SonicWall fire wall, Comodo Firewall Pro, Eset Smart security etc. Most of these firewalls combine the three approaches. In addition, they come with antivirus software and spyware protection. For big corporate computer systems, more advanced firewalls are recommended.

In conclusions, firewalls are necessary for your computer security. They may save you more than you can imagine. Therefore, it is necessary to select the best firewall for computer security.

You can get more information about Firewall For Computer Security  by IT Managed Services.