Migrating Active Directory into Linux: Many roads to Rome
Although Windows and Linux can provide similar functionality, you won't find one-to-one matching features on each platform. This is doubly true if you are migrating an Active Directory repository to Linux. It's not impossible to directly migrate user information from AD into Linux, but some of the functionality offered in AD will be expressed differently in Linux. I've written before about how Active Directory handles two basic functions: directory lookup (which Linux handles with an implementation of LDAP, such as OpenLDAP) and user authentication, which is done through Kerberos. So when you're moving from AD, the most important thing to consider is the scope of the migration -- not just in the sense of how many machines or servers, or how big a directory, but what jobs the new directory is going to take.
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