Windows XP Professional is the most popular operating system because of its ability to run the latest software and work with the coolest hardware. Windows XP is a very stable operating system.  You can leave it on for days or weeks without any problems.  But most likely, you'll have to reboot after a few weeks in order to complete installation of the latest Microsoft Windows updates.  Windows XP Professional includes Internet Information Services 5.1 (IIS 5.1).  IIS 5.1 is limited to 10 connections.  One web user will create 2-3 connections to your server at any one time, so practically, you will be able to handle about 3-4 visitors to your website simultaneously.  If you do not expect your site to deal with heavy traffic, IIS 5.1 will be fine. 

If you do plan on having more visitors, a very good combination is Windows XP Professional with Apache.  You get the ease of running Windows with the power and flexibility of Apache.  This is my top choice.

Of course there is always Linux.  Linux is a very good operating system that is very stable and runs Apache, which is the most popular webserver software in the world (for now).  A Linux system is extremely stable, has several applications available for almost anything you can throw at it.  While Windows includes networking as an add on, Linux was built around networking.  Linux with Apache webserver will make a great webserver, unfortunately, most people who just dabble in computers find Linux too difficult to configure and use.  Just wanted to let you know the option is out there.
 

What if I don't want to use PWS or IIS?

One thing I should mention is that the webserver software included in the above mentioned operating systems are not your only choice.  You can download or buy special software packages that run in almost any operating system which will turn your machine into a webserver.  For example, Apache now has a Windows version of their webserver software that you can download for free and run on your Windows machine.  I focused on the native packages because they're included with the operating system and are free, but that doesn't mean you have to use it!

An advantage of using a 3rd party software package is that you will not be limited by the 10 concurrent connection restriction built into PWS and IIS if you are not using the Server Editions of Windows.

Here is a list of free webserver and FTP software you can try out:

Web Server Software

• Apache Web Server
• Sambar Web Server
• Xitami Web Server
• Omni HTTPD Web Server
• MiniPortal - Win32 - Web server, FTP server, PHP and MySQL plug-ins
• TinyWEB Server - very small Win32 daemon for regular (TCP/http)
• TinySSL - very small Win32 daemon for secure (SSL/TLS/https)
• thttpd - tiny/turbo/throttling web server (*nix)
• mini_httpd - simple web server that does HTTPS (*nix)
• micro_httpd - world's smallest web server?  (*nix)
• BadBlue - Webserver  + Peer-to-Peer (P2P) webserver (Win32)
• E-smith - Webserver + Linux based operating system (complete solution)
• Lil HTTP Server - Webserver for Win32 machines
• WebSite - Win32 - designed for ecommerce site for a small or medium businesses
• Abyss Web Server - Win32 or Linux, supports Perl and PHP - Free
• Small HTTP Server - HTTP, FTP, SMTP, DNS, POP3, supports Perl
• MiniHTTPServer.net - Win32 - HTTP, BBS, P2P, database, photo album
• HostYourOwnWeb - Win32 - Web server, based on Apache, Graphical console, Dynamic Update Service
• KeyFocus Web Server - Win32, unlimited web sites, multiple domain names, multiple ports 

• MailEnable
• Pegasus Mail Server
• ArGoSoft Mail Server
• MDaemon Mail Server
• w3 JMail Mail Server
• CommuniGate Mail Server
• ISMail Mail Server

• Serv-U
• War FTP Server 
• Argosoft FTP Server
• BulletProof FTP Server

• Web-FTP
• Drall

• Simple DNS Plus - Software to run your own DNS servers from home

• Webhost Free - Allows you to become a simple webhost.  "WebHost Free is basically a CGI script that allows you to become your own Geocities. It allows you to automatically accept user signups and uploading from the Web."

I would strongly advise you not to use IIS for a FTP server for several reasons.  First of all, IIS doesn't have enough settings to run a FTP server from behind most routers.  The resulting FTP server may have spotty connections.  Second, IIS FTP server is highly targeted by hackers out there.  The reason is that there are a ton of people out there who have IIS installed (knowingly or unknowingly) and most of these are unsecured.  It's a popular target.  By using a 3rd party FTP software, it is less likely to be exploited.

This Step-by-Step guide here shows you how to setup a FTP Server:

• Serv-U FTP Server - Install and Setup 

Make Your Site Interactive!

• Perl - If your website requires cgi, then you need to install perl.  A good free perl program is Active State's Active Perl.  If you are using a Linux machine, perl should be installed by default.  Here is our guide on how to setup Perl on a Windows webserver: Installing Perl (ActivePerl) on a Windows Webserver
• PHP - A new script engine that is growing in popularity.  You can download the programs for Linux and Windows machines.

On the other hand, if you have batch files that you need executed when a computer is turned on without somebody logging in, take a look at Greyware Autoexec Service. This program cannot run programs as services, but what it does is run batch files once when the computer is booted up and then quits.

Webserver Security
Regardless of which operating system and  webserver software you you are using, make sure to keep an eye out for the latest patches and security updates for your software.  By running a webserver, you are out there on the web for everybody to see and hack.  Keep your webserver secure and safe.  It seems like there are new security flaws found in software everyday.  Recently, there are several instances of software worms written by hackers that can automatically find webservers with known security flaws and automatically hack into them.  This is even with firewall software and hardware in place.  What's next, GUI interface for hacking tools?

Let's put it this way, if a huge company like Microsoft can be hacked into, if NASA can be hacked into, then you can be hacked into.  A firewall and gateway isn't enough.  You need to plug up any holes in your webserver software as well.

If you use Windows, make sure to install the latest service packs and critical updates.  The easiest way to make sure that you have all the proper patches is to visit Windows Update at http://windowsupdate.microsoft.com.  When you go there, click on "Product Updates".  The first time you visit, you will be asked to install a small plugin into your web browser.  Accept this and then the system will scan your computer to see what updates you need.  Don't worry, no information is being transferred to Microsoft.  You'll then see a huge list of potential updates.  The ones you really need to pay attention to are in the "Critical Updates and Service Packs" section.  Check the appropriate boxes and hit "Download".  The updates will then be installed automatically.  Depending on which updates you install, you may or may not need to restart your computer.  You should visit Windows Update at least once a week for all your computers running Windows, no matter if it's running as a server or not.

Virus Protection
Your server should definitely run some sort of virus protection such as Norton Antivirus or McAfee Antivirus.  Many people forget to protect their server, but when you think about it, a server interacts with many people and who knows what kind of virus they might send to you, intentionally or not.  If you use Windows, make sure your virus software can run as a service, which means that the program is active even when somebody isn't logged into the computer (the software is running in the background).  I know for sure that Norton Antivirus can run as a service.  I am not sure of the other products.  Also make sure the keep your virus software is kept up to date.  A webserver will send and receive a lot of data so make the extra effort to keep your webserver clean and not a gateway for computer viruses.  This is especially true if you allow your visitors to FTP data to your server; who knows what viruses that data might contain?  If your webserver is also a email server, infected email also poses a potential threat.  As you can see, there is a lot of potential problems you can encounter with viruses so be protected!

How Do I Access My Website?
You can access your website from any web browser from the server itself, a LAN network computer, or from the Internet (WAN). Here's how.

From a computer on your network, try accessing your website by typing in the IP number of your DSL/Cable line or by typing in the domain name.  In order for this to work, your router must support "loopback".  Most routers do support loopback for web requests, but many don't for ftp requests.  If your router doesn't support loopback or if you are testing out a ftp server, then you should disconnect your computer (not the server) from your network by unplugging the network cable and then dial into a local ISP with a 56k modem so that you will be "outside" your network.
 

Depending on how your network is setup and which software package you're using, most of the techniques in the table should work, but some may not.  All in all, most should work.  Just don't freak out when one technique doesn't work, especially the http://127.0.0.1.  The one you have to make sure works is the domain name method.  That's the only one most people care about.  But if your DNS nameservers or domain name registration isn't complete yet, you can still access your website by IP address unless you're hosting multiple websites through virtual hosting and host headers.

If you are using Windows 2000 and your router doesn't support loopback, then you can try the following trick a reader emailed me:

The solution is rather simple: I had to make an entry into the hosts file which in win2k is located in \winnt\system32\drivers\etc . This entry is pointing the domain name DIRECTLY to the internal IP of the Webserver. This means, when I make a request to my domain, the request never goes beyond the router but stays inside the LAN. 

Codes, Codes, and more Codes:
As a webmaster and webserver professional, you will undoubtedly run into error codes while working on your website and while checking your log files for hackers.  You're probably familiar with "404 Not Found" but there are tons more codes.  Here is a list of what those codes actually mean.
 

Server Hardware

Troubleshooting