What is Firewall

A firewall is a software or hardware appliance that is used as a line of defense between your computer and the external threats from the internet.  Firewall technologies have evolved to meet the security requirements of the IT infrastructure. In a computer network, a firewall solution is usually implemented at the gateway computer to block the threats like intruders, hackers, viruses and unauthorized access.  There are different types of the firewall techniques and the implementation methods and the most commonly used techniques are packet filtering, proxy server, application gateway and the circuit-level gateway. 

There are many companies that produce the firewall products and the most commonly used firewall products are manufactured by Zone Alarm, Microsoft Windows Firewall, Comodo, F-Secure, Kaspersky, LavaSoft, McAfee, Symantec, R-Firewall, AShampoo and Trend Micro PC-cillin.

Firewall works very closely to a router program by examining each packet of the data.  A properly configured firewall prevent your computer form the internal and external threats. Most business class firewall products offer application layer filtering.  Application filtering is required to prevent the spam, viruses and the application layers threats. Performance is very important in the busy networks and the firewall throughput can range from 150 mpbs to 1 gbps.  Configuring the firewall requires the detailed understating of the network applications and the overall IT infrastructure. To select the best firewall product, you need to know your IT infrastructure and the level of security you require.  Most of the firewall products posses the following features.

Firewall Features

• Monitoring inbound and outbound traffic.
• User’s authentication.
• Ports blocking
• Bandwidth management
• Logging
• NAT (Network Address Translation)
• Antivirus
• Spam Filtering
• URL Screening
• Web caching
• Centralized management
• SSL
• VPN
• Email Security
• IP Spoofing
• Blocks Intrusion attempts
• Blocks viruses, spyware and other web threats.
• HTTP Filtering
• MAC Address filtering
• Remote administration
• Ports Scanning
• Application monitoring
• IP Address ban list
• Application Layer Filtering

Before selecting a firewall product you should consider the following things

• Do you prefer software firewall or hardware?
• How many concurrent connections you require.
• Do you need high availability?
• What VPN protocols do you want to use.
• Which level of security does your network require?
• How many VPN tunnels do you need to run concurrently?
• What type of user interface do you prefer?
• Authentication features.