.NET Framework 1.1 Redistributable Prerequisites


David Fleischman
.NET Framework Team
Microsoft Corporation

May 2003

Applies to:
   Microsoft® .NET® Framework
   Microsoft Windows®

Summary: Describes the redistribution of the .NET Framework for development computers and the required or recommended programs for using the .NET Framework as well as the rationale behind their installation. (5 pages)

Note: The following is an explanation of the reasons behind the prerequisites for the redistributed .NET Framework and some of the platform limitations. However, it is recommended that you meet the minimum requirements. Failure to meet minimum requirements results in a non-supported deployment. It is always highly recommended that you install the latest service packs and patches for all installed programs on the computer, including operating system service packs.


Basic Requirements
Detailed Requirements
.NET Framework Requirements for Internet Explorer 5.01
Other Dependencies for the .NET Framework

Basic Requirements

The following are the basic requirements for the .NET Framework categorized by server and client machines.

Server Definition: A computer that hosts a distributed application. This could be a Windows Server 2003, Windows XP Professional, or Windows 2000 computer. In many cases, these computers are Web servers running ASP.NET applications.

Client Definition: A computer that runs a locally installed application, such as a Windows application, that might also retrieve or process data from a remote database; or a computer that accesses a distributed, Web-based application. These computers are not required to serve information to other computers. This could be a Windows XP Professional, Windows XP Home, Windows 2000, Windows NT 4.0, Windows ME or Windows 98 computer.

Software Version Client Server
Internet Explorer 5.01 Required Required
MDAC 2.6 Required for data access Required for data access
Windows Installer 2.0 Required Required
IIS 5.0 (Windows 2000) Unnecessary Required
IIS 5.1 (Windows XP) Unnecessary Required

Basic Requirements Table

Detailed Requirements

A number of elements of the .NET Framework and underlying Common Language Runtime (CLR) rely on technologies that are delivered in optional software products or products that are not installed as part of the operating system. The following table represents the products or operating system features that the .NET Framework requires for full functionality. Because these requirements are generally enforced during the installation of the .NET Framework, the Setup Action column indicates whether setup warns or blocks the user if a requirement is not found upon installation.

Requirement Platform Setup Action Comments
Minimum of IE 5.01 Windows 98 Block  
Minimum of IE 5.01 Windows 98 SE Block  
Minimum of IE 5.01 Windows NT 4.0 Block  
Minimum of IE 5.01 Windows ME n/a IE 5.50 is already installed
Minimum of IE 5.01 Windows 2000 n/a IE 5.01 is already installed
Minimum of IE 5.01 Windows XP n/a IE 6.00 is already installed
MDAC Windows 98 None  
MDAC Windows 98 SE None  
MDAC Windows ME None  
MDAC 2.7 Windows NT 4.0 None  
MDAC 2.7 Windows 2000 None  
Service Packs      
NT4 SP6a Windows NT 4.0 Block  
SP1 Windows 2000 None SP1 is not required
SP2 Windows 2000 None SP2 is not required
IIS 4 Windows NT 4.0 None ASP.NET doesn't support Windows NT 4..0
IIS 5 Windows 2000 None  
IIS 5.1 Windows XP None  
IIS 6.0 Windows Server 2003 None  

.NET Framework Requirements for Internet Explorer 5.01

A number of elements of the .NET Framework and underlying CLR rely on technology that is part of a version of Internet Explorer. For more details on the exact Internet Explorer dependencies across the .NET Framework, see the following table.

Dependency Operating System Minimum IE Version Requirement Area
Code Download Windows 98 and Millennium 5.01 common language runtime
Code Download Windows NT 4.0 5.00 common language runtime
Code Download Windows 2000 5.01 common language runtime
Cryptography APIs All 4.01 common language runtime
Intranet / Internet Zone Detection All 4.00 common language runtime
MLang support for International encodings All 5.00 base class library

Furthermore, it is useful to understand the versions of Internet Explorer that ship with each operating system because many users run the version of Internet Explorer that came with the operating system.

Operating System IE Version Installed
Windows NT 4.0 4.01
Windows 98 4.01
Windows 98 SE 5.00
Windows 2000 5.01
Windows Millennium 5.50
Windows XP 6.00

Other Dependencies for the .NET Framework

Depending on your data access strategy, you may need to ensure that Microsoft Data Access Components (MDAC) is installed on the client computers, the business servers, the Web servers or the database servers. MDAC 2.6 is the minimum requirement for the .NET Framework and MDAC 2.7 Sp1 is recommended for servers.

If your application uses the System.Data namespace, you must install MDAC on the computer to which you are distributing.

You should ensure that you deploy the same version of MDAC to the production environment that you use in development. Visual Studio .NET ships with MDAC 2.7, so it is likely that your developers have developed and tested your solution with that version. If you subsequently deploy the application to computers where MDAC 2.6 is installed rather than MDAC 2.7, you run the risk of encountering unforeseen problems. The latest version of MDAC is available for download at Microsoft’s Universal Data Access Web site.

If your solution includes a Web tier, you must ensure that IIS and the latest security patches are installed on your target computer(s). IIS can be installed from the operating system installation CD or DVD, and the latest security patches can be downloaded and installed from the Windows Update Web site.


Question: Are there cases where a namespace or method is not supported on a platform even though the platform itself is supposedly supported?

Answer: Yes. While we've gone to great lengths to maintain a consistent set of functionality across all supported platforms, there are some exceptions to the rule. These exceptions can be found on the Exceptions to the Supported Platforms page.

Question: Why is MDAC 2.6 required?

Answer: The System.Data namespace requires MDAC 2.6 as the minimum version. If you have a version lower than MDAC 2.7 Sp1 and are installing the .NET Framework on Windows 2000 or Windows XP, you get a warning message during Setup. At runtime, the classes in System.Data verify that the MDAC version is at least MDAC 2.6.6526. If it isn't installed, they will throw an exception.