In network security, software – based firewalls (also known as server-based firewalls) are software applications that are installed in existing Operating Systems such as UNIX or Windows server platform. Advantages to a software firewall solution may include lower initial cost, at least for small networks, and the ability to combine the firewall with some other application such as a Web or FTP server, or a Cloud Hosting and a Website Hosting service. Software-based firewalls come in both small office/home office (SOHO) models and enterprise models.

In addition to server-based firewalls, personal firewalls are available for the desktop PC. Typically these are used in a SOHO environment where there is no dedicated firewall in a Dedicated Server. Some of the vendors include Zone Labs, McAfee, Norton, Tiny, and Internet Security Systems. Some of these are bundled with anti-virus software.