Kerberos: The Definitive Guide

Kerberos KDC Planning

With the Kerberos realms mapped out, now we can begin planning the implementation details for each of our new realms. Figure 9-2 shows some planning activity. In that figure, there are two KDCs (unixkdc1 and unixkdc2) for the UNIX.SAMPLE.COM realm, and they are located in the production subnet. A conscious decision was made to replicate the data located in this important realm onto two machines, to ensure high availability. In addition, because of the sensitive nature of the data located on these servers, they are separated from the customer hosting network, presumably behind a restrictive firewall that prevents attackers from gaining access to the KDCs from the hosting network, in the case one of the customer hosting machines is compromised.

Figure 9-2. Sample ISP’s network layout

Similar reasoning is used for the LABS.SAMPLE.COM Kerberos KDC placement. Only one KDC is deemed necessary for the labs realm, as it is used for experimental purposes and not for production. The KDC is placed inside the lab network to further isolate the lab environment from the rest of the network.

Next, the hardware and operating system need to be selected for these new Kerberos realms. A powerful machine is not required; the number of principals that will be located in either of these 2 realms is not great, probably under 100. Therefore, a mid-range, Intel-based machine running a free ...