Networking: A Beginner's Guide
n the early days of local area networks (LANs), finding server resources was simple.
Most organizations started with just a file server and a print server or two, so
knowing which files, printers, and other services were in which locations on the
LAN was easy.
These days, the situation is considerably more complex. Even relatively small
organizations might have multiple servers, all performing different jobs--storing
different sets of files and providing different Internet or intranet services, such as e-mail
servers, web hosting, database servers, network services, and so forth.
Directory services work to bring organization to this far-flung network clutter. In
this chapter, you learn about what directory services do and how they work. You also
learn about the directory services in use today and those slated for use in the near
future. With directory services becoming more and more central to the administration
of networks, learning this information becomes an increasingly important part of
designing, deploying, and managing networks.
What Is a Directory Service?
In most networks, you optimize the function of different services by hosting them on
different computers. Doing so makes sense. Putting all your services on one computer
is a bit like placing all your eggs in one basket--if you drop the basket, you'll break
all your eggs. Moreover, you can achieve optimal performance, more reliability, and
higher security by segregating network services in various ways.
Most networks have quite a few services that need to be provided, and often these
services run on different servers. Even a relatively simple network now offers the
File storage and sharing
Web hosting, both for the Internet and an intranet
Database server services
Specific application servers
Dial-in and dial-out services
Domain Name System (DNS) service, Windows Internet Naming Service
(WINS), and Dynamic Host Configuration Protocol (DHCP) services
Centralized virus-detection services
Backup and restore services