proxy servers: In computer networks, a proxy server is a server (a computer system or an application) that acts as an intermediary for requests from clients seeking resources from other servers. The proxy server evaluates the request according to its filtering rules
Main functions of proxy servers can be:
• To keep machines behind it anonymous (mainly for security)
• To speed up access to resources (using caching). Web proxies are commonly used to cache web pages from a web server.
• To apply access policy to network services or content, e.g. to block undesired sites.
• To log / audit usage, i.e. to provide company employee Internet usage reporting.
• To bypass security / parental controls.
• To scan transmitted content for malware before delivery.
• To scan outbound content, e.g., for data leak protection.
• To circumvent regional restrictions.
• To allow a web site to make web requests to externally hosted resources (e.g. images, music files, etc.) when cross-domain restrictions prohibit the web site from linking directly to the outside domains.
web servers: A Web server is a program that, using the client/server model and the World Wide Web's Hypertext Transfer Protocol ( HTTP ), serves the files that form Web pages to Web users (whose computers contain HTTP clients that forward their requests). Every computer on the Internet that contains a Web site must have a Web server program.
Application Servers: Application servers have lion’s share in computer territory between database servers and the end user, where servers are often connected to the two. They are often referred as middleware Middleware is that software which establishes a connection between two separate applications that are otherwise apart.
List Servers: To improve the management of mailing lists list servers are used despite of what is there type. Whether they are interactive debates open to the public or one-way lists that deliver newsletters, announcements or advertising.
Fax Servers: Those organizations that want to reduce the incoming and outgoing telephone resources; a fax server is an ideal solution. However, there is a need to fax the actual document.
Mail Servers: Mail server is as important as web server s and mail servers to send and store mails on the corporate networks through LANs and WANs and across the internet.
Chat Servers: This server enables a number of people to share information in the environment of an internet newsgroup that offer real time discussion capabilities. It is used to refer to a number of different features of computer. To immediately respond to the input real-time operating systems are used.
IRC Servers: Internet Relay Chat is comprised of various independent networks of servers that allow users to connect to each other via an IRC network. It is an option for those who are seeking real time competence.
Groupware Servers: It is software that is designed to make the users able to work together, regardless of their location, through Internet or a corporate Intranet and to work together in a virtual environment.
News Servers: They work as source of distribution and delivery for hundreds of available public news groups accessible over the USENET news network. USENET is global bulletin board system that can be approached via internet or via a variety of online services
