This is a comprehensive guide to hardening OpenLDAP on Linux using AppArmor and systemd, providing a defense in depth approach to securing LDAP deployments. The guide covers the importance of security, the role of AppArmor as a Linux Security Module, and the configuration of AppArmor profiles to restrict permissions and capabilities. It also outlines the environment used, including dedicated machines, Linux distributions, and OpenLDAP configuration. The guide emphasizes the importance of security and the need for multiple layers of defense. It highlights the potential risks of human error, software vulnerabilities, and unauthorized input, and demonstrates how AppArmor can be used to confine and restrict the permissions of OpenLDAP to prevent exploitation. The guide provides a detailed overview of the environment used, including the Linux distributions, OpenLDAP version, and Apache frontend configuration. It also touches on the use of Unix Domain Sockets and LDAPI with SASL/EXTERNAL. Overall, this guide provides a comprehensive and detailed approach to securing OpenLDAP deployments on Linux, and is a valuable resource for security professionals and system administrators.