IT Technology: Firewall (Hardware Based)

What is a firewall?

Generally, think of firewall as the security standing outside your gate. They inspect everyone that comes in and out, stop unauthorized people from entering a building, maintain a record of all entry and exits and  so on.

A firewall is not so different. It keeps a check of all incoming and outgoing connections of your computer network and based on the rules configured on the firewall, it will allow/deny access to certain computers, or technically speaking IP addresses. 

A few other things it does is it maintains a log of all incoming and outgoing connections along with the date and time stamp, shows what connections were blocked and why, and of course the best part, prevents unknown people from getting into your network from the internet.

But make no mistake. A firewall is the least you can do to secure your network – that’s right. A firewall is the most basic thing to have in place when it comes to securing your computer or an entire network.

There are two types of firewall:

1.  Hardware based firewall

These are physical machines with network ports. Commonly installed at the entry point of your network.  These are used to protect an entire network from internet threats and are generally used  at offices.

2.  Software based firewall

These are commonly associated  with antivirus software. You can download it on your Windows computer and install it yourself.  These are used to protect a single computer from internet threats. Generally used for personal use. Most popular are Norton, McAfee, Kaspersky and Comodo Firewall.

How does a firewall operate?

Before I go on telling you how does a firewall work let me talk about some general concepts of computer networking, one in particular – “IP Address”

Think of IP address similar to your physical mailing address. There is one similarity in particular – its unique. So if you have to send in a letter, you’d go to the nearest post-office, on the letter you’d write your address (source), the recipient’s address (destination) and that’s it.

A computer network operates in a similar way -  every computer or device is assigned a unique IP address using which, communication takes place. This is where a firewall comes in – the administrator would want to control, what computer(s)  should or should not communicate.

So we place a firewall in between two networks to control/monitor/log all IP communication. Most commonly, this is placed between an internal network -  A local area network or LAN

and an external network  – usually WAN or wide area network or most popularly known as the Internet.

So why would we place a firewall between your local network and the internet? That’s right, we would like to shield our internal network from external threats. By placing a firewall right in the middle, we can define certain “rules” that will tell the firewall what communication should be allowed or disallowed. After we have defined certain rules on the firewall – the firewall would check the headers of every packet (a packet is a unit of data in IP networks) and would either allow it to go through or block it. This is basically how the firewall operates.



Hardware based firewall

With so many firewalls available in the market, network administrator tends to get confused. In general, your decision should be made on the following:

1.  Performance requirements
2.  Feature requirements
3.  Cost – one time and recurring costs
4.  Support
5.  Availability of IT Consulting

A golden rule to remember – “Your firewall is only as good as your configuration”

A firewall by itself doesn't do much. It’s the firewall setup and its configuration that decides the fate of your network. So if you spend $2000 on a high-performance firewall, but don’t have the configuration done right, you’re in for a lot of trouble.

A firewall should be configured under the direct supervision of an information security expert. Once you bring in a firewall in your network, you have to make sure the firewall is configured in accordance to your company’s  IT security policy to get the most out of your expense.

Before you make a decision, be sure to have a good IT consultancy firm with security expertise or an independent IT security consultant to help you plan your network security.

References:

1.  NSS Labs 2013 Network Firewall
http://www.fortinet.com/sites/default/files/whitepapers/2013-FW-CAR.zip

2.  Enterprise Network Firewall Magic Quadrant for 2013
http://www.checkpoint.com/products/promo/gartner-firewall/