IIS limits imposed by Operating System version

The Home/Workstation versions of Windows have intentionally feature-limited versions of IIS.
Some will only support one website bound to a single IP address and/or a limited number of simultaneous users browsing the site.

You should always use a Server version of Windows for IIS in a production environment.
 
 Windows 8 (IIS v8.0)2    
RT:   No IIS
Basic:   simultaneous request execution limit of 3, allows multiple sites
Professional:   simultaneous request execution limit of 10, allows multiple sites
Enterprise:   simultaneous request execution limit of 10, allows multiple sites
     
 Windows Server 2012 (IIS v8.0)    
Server:   Server OS = No Limits
     
 Windows Server 2008 R2 (IIS v7.5)    
Server:   Server OS = No Limits
     
 Windows 7 (IIS v7.5)2    
Starter:   No IIS
Home Basic:   No IIS
Home Premium:   simultaneous request execution limit of 3, allows multiple sites
Business:   simultaneous request execution limit of 10, allows multiple sites
Enterprise:   simultaneous request execution limit of 10, allows multiple sites
Ultimate:   simultaneous request execution limit of 10, allows multiple sites
     
 Windows Server 2008 (IIS v7.0)    
Server:   Server OS = No Limits
     
 Windows Vista (IIS v7.0)2    
Starter:   No IIS
Home Basic:   No IIS
Home Premium:   simultaneous request execution limit of 3, allows multiple sites
Business:   simultaneous request execution limit of 10, allows multiple sites
Enterprise:   simultaneous request execution limit of 10, allows multiple sites
Ultimate:   simultaneous request execution limit of 10, allows multiple sites
     
 Windows 2003 (IIS v6.0)    
Server:   Server OS = No Limits
WHS:   Server OS = No Limits1
     
 Windows XP (IIS v5.1)    
Home:   No IIS
Professional:   concurrent connection limit of 10, allows only one site
     
 Windows 2000 (IIS v5.0)    
Professional:   concurrent connection limit of 10, allows only one site
Server:   Server OS = No Limits
     
 Windows NT 4 w/ SP3 (IIS v4.0)    
Workstation:   No IIS, PWS installs as part of the NT Option Pack
Server:   Server OS = No Limits, IIS installs as part of the NT Option Pack
 
 
1 Windows Home Server (WHS) is essentially Windows Server 2003 so it includes IIS v6.0  While WHS has a limit of 10 enrolled computers, there is no limit to the number of machines that may access network shares or IIS. For example, 1 user account could be used across 50 computers to access a share or authenticated site in IIS.

2 Does not include SMTP Server (normally found under IIS6 Management Console) but hMailServer is one alternative.

Small Business Server (SBS), Web, or Essentials version of the OS do not impose any special IIS limits.

There is no IIS available for Windows 95/98/SE/ME but Personal Web Server (PWS) which has a concurrent connection limit of 10.

Other web server options...
- Apache HTTP Server
- Mongoose
- SimpleHTTP
- WAMP package