You're definitely on the right track when you mention LDAP. Lightweight Directory Access Protocol (LDAP) is very popular with all Unix and Linux systems. The clients themselves use either LDAP alone, or LDAP with Kerberos, to allow them to achieve all their user management requirements. LDAP provides a centralized method of maintaining system configuration and policy information, and also simplifies systems administration.
First, you must understand that each Unix or Linux distribution will have its own client methodology of integrating services with Active directory. For example, let's look at AIX, IBM's Unix, which can be configured to allow the Unix servers to become clients to the LDAP servers running Microsoft Active Directory Server, IBM Tivoli Directory Servers and various either directory servers.
To allow AIX clients to authenticate against Active Directory, one must install "Windows services for Unix" on an Active Directory services-based system, then configure the AIX 5L clients. The AIX 5L operating system supports Active Directory services running on both Windows 2000 and 2003. You would need Services for Unix schema Version 3.0 and 3.5. You would also need to install an APAR (fixpack) to allow for this support. The APAR is IY91514 and after it is installed, it allows the support of Active Directory with the Windows 2003 R2 schema.
AIX supports two user authentication mechanisms against Windows servers, either Kerberos or LDAP authentication and Kerberos authentication. Either method allows client support with no requirement for a corresponding user account on the Unix server. On the Windows Server, you will need to make sure that Active Directory has the Unix support schema installed. You would also need to make sure that the users are Unix-enabled and if you have chosen Kerberos authentication, a host principle should be created on the Windows server.
To configure the client itself, you would use the mksecldap command to configure the clients against the Active Directory server. Type:
Do a man on this command for more options. The –c option configures the client. To set all users on the local host so that they authenticate through LDAP, type:
mksecldap -c -u ALL
For more information, look at the IBM redbook that takes you through a step by step process of configuring the clients. Good luck!
This was first published in March 2007