Stefan Norberg is an independent network security consultant based in Stockholm, Sweden. Before becoming an independent contractor, he worked for Hewlett-Packard Consulting, where he built everything from large firewalls to highly available Unix clusters. During the last couple of years, he has spent most of his time designing and implementing Internet firewalls using building blocks like Cisco IOS, HP-UX, Linux, and Windows NT/2000. Every now and then, he enjoys teaching Windows NT/2000 classes. Stefan is an MCSE+Internet and Microsoft Certified Trainer. When he finds spare time, Stefan enjoys spending it with his wife Marianne and daughter Matilda.