How Do Computer Servers Work?

Identification

Few of us work on computers that aren't connected in some way to other computers. Whether it be at work, at the library, or on the Web, if we're not running a computer server, we're most likely connected to one. Computer servers are everywhere, and each one can serve multiple functions at the same time. The actual definition for a computer server can vary. Some define it as a software application. Some define it as a computer. And some define it as a protocol, or communication language. This article will focus on the "computer" server definition, as this is its most common use. The Internet as we know it is made up of two types of users--clients and servers. Client computers make up the majority of online traffic. Servers are the ones that deliver the Web pages, emails and search engine results, while the clients are the ones making the requests.

Features

A computer server can carry out more than one server application. Many of the servers we encounter everyday have Web, email, and FTP servers as well. Each one of these applications carries out a different service. Fortunately, our Web browsers facilitate most of the communication that takes place between client and server machines.

Browser commands and domain names do much of the work that gets us where we want to go online. A website address, or domain name is made up (3) parts -

1. "http" - is the protocol used to communicate between client and server
2. "www.website.com" - is the host name, or name of the location where the site is found
3. ".address.html" - is the file name being searched

When a browser sends a request for a web page, it connects with the server that services the host listed in the IP address. The request sent by the browser is called a "GET" command. From there the server scours internet registrar sites for the address entered, then sends the file page back to our browser in an html format. Our browser translates the formatting and displays the page on our screen.

Function

The domain name addresses that we're familiar with are actually readable versions of numeric addresses, called IP addresses. IP addresses are the actual location points for each website. Registrar sites and domain name servers are specific types of computers that map all of the existing Internet addresses. What these two server types do is match up the numeric addresses with the readable addresses and provide the requested information to the Web server, which then delivers the site location to our browser.

As there are different applications for each server request type, there are different communication ports through which requests are made. A port is simply a designated communication channel that carries information requests from computer to computer. Web servers are usually assigned to port 80, whereas ftp servers are on port 21. Telnet and gopher servers also have designated ports.

Resources

• Network Computing
• Electronic Data Exchange Standards