Network Security with OpenSSL: Cryptography for Secure Communications

Implementing SSL / TLS Using Cryptography and PKI

SSH, The Secure Shell: The Definitive Guide: The Definitive Guide

Kerberos: The Definitive Guide

Secure Programming Cookbook for C and C++: Recipes for Cryptography, Authentication, Input Validation & More

DNS and BIND: Help for System Administrators

LDAP System Administration: Putting Directories to Work

sed & awk: UNIX Power Tools (Nutshell Handbooks)

SSH Mastery: OpenSSH, PuTTY, Tunnels and Keys (IT Mastery Book 12)

TCP/IP Network Administration: Help for Unix System Administrators

Active Directory: Designing, Deploying, and Running Active Directory