R&M Data Center Handbook

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File Server
This last situation is especially common with public WWW servers, because the
Internet sites that are frequented, such as search engines, large web shops or auction
houses, generate a large quantity of data for processing. In this case, so-called loadbalancing
systems come into play. They are programmed to distribute incoming
queries to several physical servers.
The following basic types of server services exist:
A file server is a computer attached to a network that provides shared access to computer files for workstations
that are connected to the computer network. This means that users can send each other files and share them via
a central exchange server. The special feature offered by file servers is that using them is as transparent as using
a local file system on workstation computers. Management of access rights is important, for not all users should
have access to all the files.
Print Server
A print server or printer server allows several users or client computers shared access to a printer or printers. The
biggest challenge is to automatically provide the client computer with the appropriate printer driver for their
respective operating system so that they can use the printer without having to install the driver software locally.
Mail Server
A mail server, or message transfer agent (MTA), does not necessarily have to be installed on an Internet
provider's server, but can operate on the local network of a company. First, it is often an advantage when
employees can communicate with each other by e-mail, and second, it is sometimes necessary to operate an
internal e-mail server just because Internet access is heavily restricted for security reasons, or communication
between workstations and external mail servers is not allowed in the first place.
Web Server
The primary function of a web server (HTTP server) is to deliver web pages from a network to clients on request.
Usually, this network is the public Internet (World Wide Web). This form of information transfer is becoming more
and more popular in local company networks (intranet). The client uses a browser to display, request and explore
web pages, and also to mouse-click to follow the hyperlinks contained within those pages, which are links to other
websites, files, etc. on the same or a different server.
Directory Services (DNS server)
Directory services are becoming increasingly important in IT. A directory in this context is not a file system but an
information structure, a standardized catalog of users, computers, peripherals and rights in a network. Information
can be accessed network-wide via an entry in this directory, which means that directory services are a practical
basis for numerous services, making work easier for administrators and life easier for users in large network
environments. Here are some examples:
• Automatic software distribution and installation
• Roaming user profiles
• Single sign-on services
• Rights management based on computer, clients and properties
Application Server
An application server allows users on a network to share software applications on the server.
• This can be a server in the LAN, which runs applications that are frequently used by clients (instead of
pure file server services).
• Or it runs the application/business logic of a program (e.g. SAP R/3 ® ) in a three-tier architecture (see
section 3.3.1.), interacts with database servers and manages multiple client access.
• Or it is a web application server (WAS) for web applications, dynamically generating HTML pages (or
providing web services) for an Internet or intranet connection.
Web services are automatic communication services over the Internet (or intranet) which can be found, interpreted
and used through established and standardized procedures.
Page 6 of 156 © 08/2011 Reichle & De-Massari AG R&M Data Center Handbook V2.0