Mac OS X in a Nutshell

NetInfo Concepts

Mac OS X keeps all its administrative information in NetInfo. Understanding how NetInfo works is important to performing all but the most basic administrative tasks in Mac OS X.

Every Mac OS X machine, whether a solitary home computer or part of a local network, has access to a NetInfo database. NetInfo functions as a directory service. Processes running on your Mac can query NetInfo for information about the machine’s users, printers, network services, mounted filesystems, and so on. Processes owned by users with administrative credentials can also modify NetInfo.

Literally speaking, the database runs through a process running locally called netinfod, which acts as an interface to some on-disk binary files. NetInfo’s real strength lies in the fact that this daemon can be bound to others running on different machines, creating a distributed NetInfo database. Network administrators can use this feature to create sophisticated hierarchies of shared administrative information among many Macs.

To see how this works, we’ll examine the concept of a NetInfo domain.

NetInfo Versus Flatfiles

Most Unix systems store administrative information in world-readable, root-writable flatfiles that are stored in traditional spots around the machine, especially in the /etc/ directory. One can usually find a list of the machine’s users in /etc/passwd, for example, and a description of global mail aliases in /etc/alias. A default Mac OS X system also has many of these files, as a glance ...