Acknowledgments

This book is a companion to NetSim, a browser-based network simulator and firewall teaching tool. NetSim is a modern successor to the iNetwork Simulator built at the University of Technology Sydney, described in Ye and Sandrasegaran’s 2006 IEEE paper on teaching firewall concepts.

NetSim uses a curated subset of real Linux syntax and errors loudly on anything outside it. That design choice shapes this book: the commands are meant to travel to a real machine within the documented subset.