Different types of Servers

Different types of Servers used in networks are listed below.

File Server: File servers are used to store the user documents and files centrally. An ideal file server should have a large amount of memory and storage space, fast hard-disks, multiple processors, fast network adapters, redundant power supplies etc.

A File server runs FTP (File Transfer Protocol) in Windows, Linux or Unix Networks, or SMBP (Server Message Block Protocol) in Windows Networks. Well known FTP software products are Micrsoft IIS, vsftpd, Apache FTP Server etc.

The main advantage of keeping network user files and electronic documents centrally in a file server is that the network user files and documents can be managed (backup'd) easily. Think about managing network user files and electronic documents kept distributed inside user workstations in a network consists of thousands of computers! Nearly impossible.

Print Server: Print Server, which redirects print jobs from client computers to specific printers.

Mail Server: Mail Servers are used to transmit emails using email protocols. Most widely used email transmission protocol is SMTP (Simple Mail Transfer Protocol). Mail Servers exchange emails between different domains.

Most widely used Mail Server software products are Microsoft Exchange Server, SENDMAIL (now proofpoint), qmail,Postfix etc.

Application Server: Common computer applications or programs which are required by different network users can be run in a central server, which enables multiple network users to access common network applications from the network. Typically Application Servers run business logic. Which means, every business is different and the Application Server is the Server Software which controls the business process. Some examples for Application Server Software are SAP BASIS, WebLogic, WebSphere etc.

Database Server: Database Server allows authorized network clients to create, view, modify and/or delete an organization's data, stored in a common database.

Examples of Database Management Systems are Oracle 10g/11g, Microsoft SQL Server 2000/2005/2008/2012, PostgreSQL,IBM DB2, MySQL, Sybase, Informix etc.

Directory Servers: Directory Servers allows the central administration and management of network users and network resources. Directory Servers provide the basic functions of network security, Authentication, Authorization and Accounting.

Examples of Directory Servers are Microsoft Active Directory, NetIQ eDirectory, Fedora Directory Server, OpenLDAP etc.

Another logical classification of computer networks is Centralized and Distributed Computer Network Model.

Centralized computer network model

In Centralized computer network model, the network resources are placed and managed from a main location. Centralized network model allows administrators to manage the resources centrally (typically in Head Office). The network servers and other critical network resources are located in a central location in a secure and dedicated server room.

Centralized network model provides following advantages to Network and System Administrators.

Centralized network model provides Network and System Administrators better access to network devices

In Centralized network model, Network Resources can be managed more easily

Centralized network model provides better Network Security.

The main disadvantage is more work load of Network and System Administrators and increased risk of communication failure due to a catastrophe in the central location.

Distributed network model

In Distributed network model, the network resources are placed and managed from different geographical locations. Designated network and system administrators manage the network resources in different locations. These days most of the Enterprise network models are distributed.