In this chapter, we discussed LDAP, Kerberos installation and configuration, setting up LDAP with Kerberos. We used Kerberos security for SSH logins, discussed SSH server and passwordless SSH setup between two machines, discussed how to disable password-based authentication and limit the users who can SSH into the system. Finally, we saw how to greet users with banners.
In the next chapter, we will study the monitoring and optimization of our Ubuntu Server. We will discuss CPU load, storage, network, and monitoring with tools such as Nagios, Munin, and more.