Types of Web Servers are:
1. Mail Server
Mail Servers provides a centrally-located pool of disk space for network users to store and share various documents in the form of emails. Since, all the data is stored in one location, administrators need only backup files from one computer.
2. Application Server
An application server acts as a set of components accessible to the software developer through an API defined by the platform itself. For Web applications, these components are usually performed in the same running environment as its web server(s), and their main job is to support the construction of dynamic pages.
3. File Transfer Protocol (FTP) Server
FTP uses separate control and data connections between the client and the server. FTP users may authenticate themselves in the form of a username and password, but can connect anonymously if the server is configured to allow it. For secure transmission username and password must be encrypted using FTP and SSL.
4. Database Server
A database server is a computer program that provides database services to other computer programs or computers using client-server model. Database management systems frequently provide database server functionality, and some DBMSs (e.g., MySQL) depend on the client-server model for database access.
Such a server is accessed either through a “front end” running on the user’s computer where the request is made or the “back end” where the request is served such as data analysis and storage.
5. Domain Name System (DNS) Server
A name server is a computer server that hosts a network service for providing responses to queries. It maps a numeric identification or addressing component. This service is performed by the server in response to a network service protocol request.
The primary function of these DNS servers is the translation (resolution) of human- memorable domain names and hostnames into the corresponding numeric Internet Protocol (IP) addresses. The secondary function of DNS is to recognize a name space of the Internet, used to identify and locate computer systems and resources on the Internet.