IIS Architecture Overview
IIS architecture has changed over time. Understanding the architectural features of a specific version of IIS can help you decide how to design an application for IIS.
Comparison of IIS Versions
The following table summarizes the important differences between versions of IIS.
Feature |
IIS 4.0 |
IIS 5.0 |
IIS 5.1 |
IIS 6.0 |
|---|---|---|---|---|
Platform |
NT4 |
Windows 2000 |
Windows XP Professional |
Windows Server 2003 |
Architecture |
32-bit processor |
32-bit processor |
32-bit and 64-bit processors |
32-bit and 64-bit processors |
Application process model |
TCP/IP kernel Inetinfo.exe runs in-process applications (low isolation) MTX.exe runs out-of-process applications (high isolation) |
TCP/IP kernel Inetinfo.exe runs in-process applications (low isolation) Multiple DLLhost.exe processes run pooled-process or out-of-process applications (medium or high isolation) |
TCP/IP kernel Inetinfo.exe runs in-process applications (low isolation) Multiple DLLhost.exe processes run pooled-process or out-of-process applications (medium or high isolation) |
HTTP.sys kernel When IIS is running in IIS 5.0 isolation mode: Same process model as for IIS 5.0 When IIS is running in worker process isolation mode: W3Wp.exe (multiple worker processes) For more information about the IIS 6.0 process model, see Worker Processes in IIS 6.0 |
Metabase configuration file type |
Binary |
Binary |
Binary |
XML-formatted |
Security |
Windows authentication SSL |
Windows authentication SSL Kerberos |
Windows authentication SSL Kerberos Web Server Certificate Wizard |
Windows authentication SSL Kerberos Web Server Certificate Wizard Microsoft. NET Passport support |
Remote administration |
HTMLA |
HTMLA |
No HTMLA Terminal Services |
Remote Administration Tool (HTML) Web Server Appliance Kit (SAK) Terminal Services |
Administration technologies |
ADSI and ABO |
ADSI and ABO |
ADSI and ABO |
ADSI, WMI, and ABO |
Cluster support |
Windows support |
IIS clustering |
Windows support |
Windows support |
WWW services |
IIS on NT 4.0 Personal Web Manager on Windows 95 and Windows 98 |
IIS on Windows 2000 Server and Windows 2000 Professional (IIS is not installed by default on Windows 2000 Professional) |
IIS on Windows XP Professional (IIS is not installed by default) |
IIS on Windows Server 2003 (IIS is not installed by default) |