What is a software firewall ?

A software Firewall is just that.  A piece of software.  An example of this is installing a firewall such as Zone Alarm or Trend Micro’s firewall on a computer that is directly connected to the internet.  It is a program that monitors the traffic at the interface level and blocks any un-wanted traffic.  While this type of software is better than nothing, it traditionally is vulnerable to issues directly related to the hardware it is installed on.  An example is some sort of bug relating to the interface of the laptop that could allow data to leak.  The software firewall would not be able to protect against this sort of data loss and could leave the users computer vulnerable.

Now the largest Security Vendor of security software is Check Point and it has always been a software company.  But, this software was certified for certain hardware types and could only be installed on specific platforms.  While this is in a sense a software firewall, it is not software that is just installed on a laptop.  Check Point has recently moved to its own hardware firewalls to make it easier to get into markets that were mainly hardware oriented.