For PowerPC based Macintosh computers under OS 9 (9.2+) or OS X (10.1.5+).

Free, dynamic, application-level personal firewall, and of TrueVector technology for real-time Internet traffic information and control. Includes a profile, product range, support, and online purchasing.

Blocks all externally originated IP traffic, making computer invisible to outsiders. Also detects alterations to files so as to block Trojans. Free for personal use. Site contains overview, manual, FAQ, screenshots and prices.

Personal firewall for Windows developed with the open architecture model, and supporting plug-ins for additional functionality. Includes an overview, features, benefits, pricing, and software downloads.

Firewall Plus is free personal firewall for MS-Windows based computers.

Free personal firewall with application database.

Trustix Personal Firewall includes a spyware killer and Pop-Up Stopper. A free 30 day trial version is available.

Free PC firewall protection has integrated application based intrusion prevention, firewall features, built-in security scan, and forensic logging. Offers downloads, products, online purchasing, and support.

Offers am enterprise class host-based intrusion prevention system.

Firewall protection for Mac that keeps hackers out and personal data in