WebJunction

Computer networks can range from a simple peer-to-peer network to a more complex client-server network. While a complicated network can generally perform more advanced functions, it requires more involved planning, particularly regarding the server application.

If you have a client-server network, you are probably using the server to share files and printers, and you may also be using it to host a Web site or e-mail. If you are, then you probably are using server applications. If you aren't, then you need them.

Servers are designed for nearly every purpose imaginable, from simple e-mail servers to more complicated application servers. Every application will have specific server requirements, and is typically designed to run on Windows NT/2000, Novell Netware, or Linux.

Many servers can run multiple applications to serve a variety of needs. As your network grows, you will find uses for a variety of specialized server applications. The following is just a brief introduction to the most common types of server applications.

File and print servers

File and print servers are typically combined on one server and perform as part of the network operating system. The file and printer servers manage the storage of data and the various printers on the network. These servers regulate and monitor access to these resources.

The three most popular are:

·        Microsoft Windows NT 4

·        Microsoft Windows 2000

·        Novell Netware 5.1

Mail servers

Mail servers manage local (within your network) and global (Internet-wide) electronic messaging. The mail server you choose should support the Internet standards such as POP3 and SMTP. Sometimes they even incorporate entire groupware solutions: managing calendars, contacts, group meeting scheduling, and other operations.

There are many examples of mail servers, but the most popular are:

·        Microsoft Exchange

·        Eudora Mail Server

List servers

While many mail servers offer the capability to serve an e-mail listserv or mass e-mail distribution, there are some servers that handle those tasks exclusively.

Here are a few to look at:

·        LISTSERV

·        Lyris

·        Arrow Mailing List Server

Fax servers

Fax servers manage fax traffic in and out of the network, allowing multiple users to send and receive faxes without a fax machine. Most of the popular e-mail servers have fax servers that you can buy and integrate into your system, so look there first. One interesting note is that Microsoft Small Business Server (basically their BackOffice software for fewer than 30 users) includes a fax server. However, they didn't include it in Windows 2000.

Some other examples of standalone fax servers are:

·        RelayFax

·        FaxMaker

Web servers

Web servers allow Internet users to attach to your server to view and maintain Web pages. Web browsers such as Netscape and Internet Explorer request documents from the Web server using standard protocols, and the Web server retrieves the requested documents and forwards them on to the browsers. Web servers support a variety of technologies including CGI scripts, Active Server Pages, and secure connections to extend the power beyond the basic HTML code.

The two most popular Web servers are:

·        Apache (for “A patchy†Web server)

·        Microsoft Internet Information Services (IIS)

One interesting thing is that this field is primarily the domain of Linux and Unix (with Apache). However, Microsoft has been playing catch-up, and it is gathering support around its IIS product.

Database servers or database management systems (DBMS)

Though not exactly a server, DBMS systems allow multiple users to access the same database at the same time. While this functionality is typically built into database software (ex. Microsoft Access allows concurrent connections to its databases), a larger database, or a database with many users, may need a dedicated DBMS to serve all the requests. Examples of these include:

·        Microsoft SQL Server

·        IBM DB2

·        Oracle's Database Management Products

Application servers

Application servers have undergone many changes and have grown in both quantity and variety with the growth of the Internet. Basically, an application server acts as an intermediary to information. Here is a typical situation:

1. A client makes a request for information (often as a database request).

2. The application server passes that request on to the application.

3. The application processes the request and sends the results to the application

server, which then returns the results to the client.

4. The client gets the results of their query without needing to download the

whole database to his or her workstation.

In many usages, the application server works with a Web server and is called a Web application server. The Web application server receives requests from a Web page then returns the information in a new Web page based on the results and uniquely created. The technology to do this typically involves the Common Gateway Interface (CGI) Microsoft's Active Server Pages (ASP) , or Java Server Pages (JSP). Examples of application servers include Cold Fusion.

Once again, this is just the tip of the iceberg. There are many more application servers available. For a more detailed introduction to all of these servers see: DevX.com.

Terminal servers or communication server

Generally, a terminal server refers to a piece of hardware that allows devices to be attached to the network without a need for network cards. PCs, “dumb†terminals supporting just a mouse and monitor, or printers can all be attached via standard ports, and can then be managed by the network administrator.

However, Microsoft has co-opted this term and changed it to fit their purposes. A Microsoft Terminal Server is a program running on its Windows NT 4.0 operating system that provides the graphical user interface of the Windows desktop to user terminals that don't have this capability themselves. The latter include the relatively low-cost Net PCs or “thin clients†that some companies are purchasing as alternatives to the autonomous and more expensive PC with its own operating system and applications. In the past, Terminal Server required an entirely different operating system version, but Microsoft has expanded this capability to be a standard application in Windows 2000.

Proxy servers

Proxy servers act as intermediaries between your network users and the wide world of the Internet. Proxy servers perform a number of functions:

·        Masks your network users IP addresses

·        Strengthens security by only allowing certain requests to come through and by providing virus protection

·        Caches Web page data for a given period of time to allow for more rapid access

Examples of proxy servers include:

·        Microsoft Proxy Server

·        Wingate

Conclusion

The preceding list is only an introduction to common server applications. With the amount of time and money thrown at the Internet, many types of servers are springing up to fill every conceivable need. Whether you need to start up an e-mail list, or provide access to talk radio 24 hours a day, there is a server for you. For a detailed examination of the various types and competitors in each of these markets, we recommend visiting the holy grail of server information: ServerWatch.