Part IV consists of the following summary appendices:

Appendix A, Resources, contains a list of places you can go for further information and help with Internet security -- World Wide Web pages, FTP sites, mailing lists, newsgroups, response teams, books, papers, and conferences.

Appendix B, Tools, summarizes the best freely available Internet security tools and how you can get them.

Appendix C, TCP/IP Fundamentals, contains background information on TCP./IP that is essential for anyone who is building or managing a firewall. This appendix is excerpted from Craig Hunt's excellent book, TCP/IP System Administration.