Guide to Linux Networking and Security is a hands-on, practical guide that can be used to master Linux networking and security, in preparation for the Linux certification exams from SAIR/GNU and LPI. This book begins by introducing networking technologies and protocols, then moves into configuring a Linux network using a variety of command line and graphical utilities. Specific protocols and applications are covered in the networking chapters, including the r-utilities, NFS, Samba, and FTP, plus business-critical services such as e-mail, Web, and DNS. The second half of this book includes a discussion of security in the context of protecting business assets and user privacy, with emphasis on system administrator ethics. Cryptography and encrypted protocols lay a foundation for discussion of specific Linux security tools, including PAM, sudo, and GPG. User, file, and network security are covered. The network security discussion includes firewalls, VPNs, and utilities such as nmap, ethereal, and the SAINT profiling tool. Throughout, the book provides examples of sample commands and output, plus screen shots of related graphical utilities.