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BaseAddressPrefixFilterElement Class

Represents a configuration element that specifies a pass through filter, which provides a mechanism to pick the appropriate IIS bindings when hosting a Windows Communication Foundation (WCF) application in IIS. This class cannot be inherited.

Namespace:  System.ServiceModel.Configuration
Assembly:  System.ServiceModel (in System.ServiceModel.dll)

public sealed class BaseAddressPrefixFilterElement : ConfigurationElement

A prefix filter provider a mechanism for a service to bind to a specific URI .It enables you to host multiple applications with different base addresses for the same scheme on the same site.

IIS websites are containers for virtual applications which contain virtual directories. The application in a site can be accessed through one or more IIS binding. IIS bindings provide two pieces of information: binding protocol and binding information. Binding protocol (e.g., HTTP) defines the scheme over which communication occurs, and binding information (e.g., IPAddress, Port, Hostheader) contains data used to access the site.

IIS supports specifying multiple IIS bindings per site, which results in multiple base addresses per scheme. Since a WCF service hosted under a site allows binding to only one base address per scheme, you can use the prefix filter feature to pick the required base address of the hosted service. The incoming base addresses, supplied by IIS, are filtered based on the optional prefix list filter.

For example, your site can contain the following base addresses

You can use the following configuration file to specify a prefix filter at the appdomain level.

        <add prefix=”net.tcp://”/>
        <add prefix=””/>

In this example, net.tcp:// and are the only base addresses for their respective schemes which are allowed to be passed through.

By default, when prefix is not specified, all addresses are passed through. Specifying the prefix will result in only the matching base address for that scheme to be passed through.


The filter does not support any wildcards. In addition, the baseAddresses supplied by IIS may have addresses bound to other schemes not present in the baseAddressPrefixFilters list. These addresses are not filtered out.


Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5 SP1, 3.0 SP1