Chapter 14 Security

Table of Contents
14.1 Synopsis
14.2 Introduction
14.3 Securing FreeBSD
14.4 DES, Blowfish, MD5, and Crypt
14.5 One-time Passwords
14.6 TCP Wrappers
14.7 KerberosIV
14.8 Kerberos5
14.9 OpenSSL
14.10 VPN over IPsec
14.11 OpenSSH
14.12 File System Access Control Lists
14.13 Monitoring Third Party Security Issues
14.14 FreeBSD Security Advisories
14.15 Process Accounting
Much of this chapter has been taken from the security(7) manual page by Matthew Dillon.

14.1 Synopsis

This chapter will provide a basic introduction to system security concepts, some general good rules of thumb, and some advanced topics under FreeBSD. A lot of the topics covered here can be applied to system and Internet security in general as well. The Internet is no longer a “friendly” place in which everyone wants to be your kind neighbor. Securing your system is imperative to protect your data, intellectual property, time, and much more from the hands of hackers and the like.

FreeBSD provides an array of utilities and mechanisms to ensure the integrity and security of your system and network.

After reading this chapter, you will know:

Before reading this chapter, you should:

Additional security topics are covered throughout this book. For example, Mandatory Access Control is discussed in Chapter 16 and Internet Firewalls are discussed in Chapter 28.

This, and other documents, can be downloaded from

For questions about FreeBSD, read the documentation before contacting <>.
For questions about this documentation, e-mail <>.