| IIS 4.0
| IIS 5.0
| IIS 5.1
| IIS 6.0
|
Platform
| Windows NT 4.0
| Windows 2000
| Windows XP Professional
| Windows Server 2003
|
Architecture
| 32-bit
| 32-bit
| 32-bit
| 32-bit and 64-bit
|
Application process model
| TCP/IP kernel and DLL host
| TCP/IP kernel and DLL host
| TCP/IP kernel and multiple DLL
| http.sys kernel and multiple worker processes
|
Metabase configuration
| Binary
| Binary
| Binary
| XML
|
Security
| Windows Authentication
| Windows Authentication, Kerberos, and SSL
| Windows Authentication, Kerberos, SSL, and Security Wizard
| Windows Authentication, Kerberos, SSL, Security Wizard, and Microsoft Passport
|
Remote administration
| Not supported
| HTMLA
| No HTMLA and Terminal Services
| No HTMLA, Web Blade UI, and Terminal Services
|
Cluster support
| None
| IIS clustering
| Windows support
| Windows support
|
Web Services
| IIS on Windows NT 4.0
| Personal Web Manager on Windows 9x and IIS on Windows 2000
| IIS option for Windows XP and IIS on Windows 2000
| IIS on Windows Server 2003
|