| Lesson 3 || Server types and functions |
| Objective || Describe types of servers and their functions. |
Server Types and Functions
The basic function of a server is to manage network resources accessed by network clients.
The term "server" can refer both to a program that performs these operations and to a machine that runs one or more server programs. The following table lists servers by class (or purpose). LAN administrators can mix and match server functions without regard to their class, but it's helpful to see the role the servers play relative to Web, firewall, email, DNS, or LAN duties.
A proxy server sits between a client program (typically a Web browser) and an external server (typically another server on the Web) to filter requests, improve performance, and share connections.
- Mail Server: Almost as ubiquitous and crucial as Web servers, mail servers move and store mail over corporate networks (via LANs and WANs) and across the Internet.
- Server Platforms: A term often used synonymously with operating system, a platform is the underlying hardware or software for a system and is thus the engine that drives the server.
- Web Server: At its core, a Web server serves static content to a Web browser by loading a file from a disk and serving it across the network to a user's Web browser. This entire exchange is mediated by the browser and server talking to each other using HTTP.
- Application Server: Sometimes referred to as a type of middleware, application servers occupy a large chunk of computing territory between database servers and the end user, and they often connect the two.
- Real-Time Communication Server: Real-time communication servers, formerly known as chat servers or IRC Servers, and still sometimes referred to as instant messaging (IM) servers, enable large numbers users to exchange information near instantaneously.
- FTP Server: One of the oldest of the Internet services, File Transfer Protocol makes it possible to move one or more files securely between computers while providing file security and organization as well as transfer control.
- Collaboration Server: In many ways, collaboration software, once called 'groupware,' demonstrates the original power of the Web.
Collaboration software designed to enable users to collaborate, regardless of location, via the Internet or a corporate intranet and to work together in a virtual atmosphere.
- List Server: List servers offer a way to better manage mailing lists, whether they be interactive discussions open to the public or one-way lists that deliver announcements, newsletters or advertising.
- Telnet Server: A Telnet server enables users to log on to a host computer and perform tasks as if they're working on the remote computer itself.
- Open Source Server: From your underlying open source server operating system to the server software that help you get your job done, open source software is a critical part of many IT infrastructures.
- Virtual Server: In 2009, the number of virtual servers deployed exceeded the number of physical servers.
Today, server virtualization has become near ubiquitous in the data center. From hypervisors to hybrid clouds, ServerWatch looks at the latest virtualization technology trends.
In the next lesson, you will learn how to estimate a server's transfer load.
Classification Server - Types