Web Servers Demystified

Do you know how a web page is appearing in your browser when you open it in a browser? Do you know from where the images or audio has been appearing in any web page? They are all from some web servers. A Web server is a piece of computer software that can respond to a browser's request for a page, and deliver the page to the Web browser through the Internet. When you call a web page by its address, the URL, for example, http://www.macronimous.com/default.asp, then what happens exactly between your computer and the web server where the site is hosted? Let us discuss everything you want to know about a web server in this article.

• If you call the URL(Uniform Resource Locator) http://www.macronimous.com/default.asp in your browser, the browser will split-up and understand the three parts,
  • The http (Hyper Text transfer Protocol),
  • The server name where the site is hosted and
  • The web page under the site, default.asp.
• The browser will communicate with a name server to translate the server name "www.macronimous.com" into an IP (Internet Protocol) Address, which it uses to connect to the server machine.
• Then the browser will form a connection to the server at that IP address on port 80.
• By following the HTTP protocol, the browser sent a GET request to the server, asking for the file "http://www.macronimous.com/default.asp".
• Since the browser can understand only HTML Tags, the web server will interpret the server-side scripting and will send the files in HTML format to the Browser. For example, An IIS web server can interpret ASP scripting and will send the browser as a HTML file.
• Then the browser will interpret the HTML tags into formatted web pages, as you see in the browser.

Web Server helps people to create both static and dynamic pages. All HTML pages(with or without client-side scripts) are static, means, the html files will be sent to the browser without any intervention of the web server. But when you write some server side script that can make the site dynamic, here the presence of web server helps us to achieve the dynamic page. For example if you write a GuestBook in ASP then a web server, here IIS, is needed to interpret it. The Web server is actually processing information and generating a page based on the specifics of the query.

A web server can provide security to your pages to some level. A web server with SSL (secured Socket Layer) can give you more protected pages, where you can do secured file transaction like credit card processing. As we previously said web servers can run your server side scripting. Here is the list of some web servers and what server side scripts they can run.

The following is the complete web comparison chart, tells about the platforms which they run and their cost.

web server Version Operating System Price(Approx.)/Remarks ACME thttpd   FreeBSD, SunOS 4, Solaris 2, BSD/OS, Linux, OSF Free Amiga Web Server   Amiga Free Apache 1.3.17 NetBSD, Digital UNIX, AIX, OS/2, Windows 3.x, SCO, HPUX, Novell NetWare, Macintosh, Be OS, Windows NT, Linux, VMS, AS/400, Windows 95, FreeBSD, IRIX, Solaris Free CERNHttpd       Commerce Server/400 1.0D AS/400 $4995 (suggested retail) EMWAC HTTP Server 0.991 Windows NT Free GoAhead web server 2.1 HPUX, Embedded, Windows NT, Linux, Windows CE, QNX, Windows 95, Windows 98, IRIX Free, embedded web server Hawkeye 1.3.5 Linux Private/educational use - free Internet Information Server 5.0 Windows 2000 Free with Win2000 server Jigsaw 2.1.2 Win95, WinNT and Solaris 2.x. OS/2, MacOS, BeOS, Linux, AS-400 and AIX with JDK1.2 and above Free, W3 license Lotus Domino Go web server 4.6.1 Digital UNIX, AIX, OS/2, HPUX, Windows NT, Windows 95, IRIX, Solaris $495; free demo Netscape Enterprise (AOL) web server 6.0   Solaris 2.6, 7, 8 &Windows NT 4 SP6a, 2000 Server SP1 or later N/A RapidControl for Web(tm) 3.01 NetBSD, Digital UNIX, BSDI, Windows 3.x, SCO, HPUX, Windows NT, Linux, MS-DOS, Windows 95, FreeBSD, IRIX, Solaris Write to sales@rapidlogic.com Savant 2.1 Windows NT, Windows 95, Windows 98 Free Spinnaker 3.0 Windows NT, Windows 95 $249 Spyglass MicroServer 2.0 Embedded, Windows NT, Linux, Solaris contact Spyglass Stronghold Secure Web Server 3.0 NetBSD, Digital UNIX, BSDI, AIX, SCO, HPUX, Linux, FreeBSD, IRIX, Solaris Contact c2.net Sun ONE web Server   Sun Solaris[tm] 8, 7, and 2.6,Microsoft Windows NT 4.0 SP6a, Microsoft Windows 2000 SP1 or later, Red Hat Linux, Hewlett-Packard HP-UX, Compaq Tru64 UNIX 5.0a $1495 Sun Chili!Soft ASP Server   Sun Solaris[tm] 8, 7, and 2.6 (SPARC® platform),Microsoft Windows NT and 2000,AIX 4.3.3,HP-UX 11.0 Plug-In/ $495 Viking 1.06 Windows NT, Windows 95, Windows 98 $100 for 90-day trial WebBase 4.5 NT 4, 95, 98, 2000 $995-$1795 WebSTAR 5.0 5.0 MacOS X $399 WebSite Pro 3.1.13.0 2.5.8 Windows NT, Windows 95, Windows 98 $299 - $1999 WebTen 2.1 Macintosh $495 Xitami 2.4d9   NetBSD, Digital UNIX, BSDI, AIX, OS/2, Windows 3.x, SCO, HPUX, Windows NT, Linux, VMS, QNX, Windows 95, FreeBSD, IRIX, Solaris free/ $250 Zeus Web Server 4.0 NetBSD, Digital UNIX, BSDI, AIX, SCO, HPUX, Linux, FreeBSD, IRIX, Solaris $1700

Note: The above table is prepared with the prices, specified in the corresponding websites on December 2002.