Firewall

• A firewall is a security device that can be a software program or a dedicated network appliance. 
• The main purpose of a firewall is to separate a secure area from a less secure area and to control communications between the two.
  

Software Firewalls:

• Software firewalls, also sometimes called personal firewalls, are designed to run on a single computer. 
• These are most commonly used on home or small office computers that have broadband access, which tend to be left on all the time. 
  
• A software firewall prevents unwanted access to the computer over a network connection by identifying and preventing communication over risky ports. 

Hardware Firewalls:

• Hardware firewalls are more complex. 
• They also have software components, but run either on a specially engineered network appliance or on an optimized server dedicated to the task of running the firewall.