Recipe 18.7 Integrating with MIT Kerberos

18.7.1 Problem

You want to integrate your existing MIT Kerberos infrastructure with Active Directory.

18.7.2 Solution

Integrating MIT Kerberos with Active Directory typically means setting up a trust between an Active Directory domain and your MIT Kerberos realm. Creating a trust between a domain and realm is the first step toward Kerberos interoperability. It will allow users to access resources in either the AD domain or Kerberos realm. Here are the steps to create the trust:

1. Create a trust to the Kerberos realm on a domain controller:

   > netdom trust AD.RALLENCORP.COM /Domain:MIT.RALLENCORP.COM /Add /Realm /[RETURN] PasswordT:"Password"

2. Make the trust transitive (if necessary):

   > netdom trust AD.RALLENCORP.COM /Domain:MIT.RALLENCORP.COM /Transitive:yes

3. Add a KDC for the Kerberos realm on the domain controller(s):

   > ksetup /addkdc MIT.RALLENCORP.COM kdc01.mit.rallencorp.com

4. Add the AD domain principal to the Kerberos realm (on the Unix host):

   kadmin: addprinc -e des-cbc-crc:normal krbtgt/ad.rallencorp.com

18.7.3 Discussion

What I've shown here is just the tip of the iceberg. You may need to configure service principals, create account mappings, create host principals, and tweak the krb5.conf configuration file on your MIT KDCs to accomplish full integration in your environment. Providing details on how to do all of that is beyond the scope of this book, but a great resource on Kerberos is O'Reilly's Kerberos: The Definitive Guide, which covers all the ins and outs of the Kerberos protocol and interoperability with Active Directory. Also, there are some good resources on the Web, which I've listed here:

• MIT Kerberos home page (http://web.mit.edu/kerberos/www/)

• Microsoft's Step-by-Step Guide to MIT Kerberos Interoperability (http://www.microsoft.com/windows2000/techinfo/planning/security/kerbsteps.asp)

• Windows 2000-MIT Kerberos Interop Trip-ups (http://calnetad.berkeley.edu/documentation/test_environment/kerb_interop_trip-ups.html)

18.7.4 See Also

MS KB 217098 (Basic Overview of Kerberos User Authentication Protocol in Windows 2000), MS KB 230476 (Description of Common Kerberos-Related Errors in Windows 2000), MS KB 248758 (Information About the Windows 2000 Kerberos Implementation), MS KB 324143 (HOW TO: Use the Kerberos Setup Tool (Ksetup.exe)), and MS KB 810755 (White Paper: Windows 2000 Kerberos Interoperability and Authentication)