Article ID: 928906 - View products that this article applies to.
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When you create an application to establish a virtual private network (VPN) tunnel in Windows Vista, the value that is returned by an API function is not what you expect. The remote access service incorrectly registers the VPN tunnel as an "IF_TYPE_PPP" Network Driver Interface Specification (NDIS) network interface type.
This problem occurs because the remote access service incorrectly registers a Point-to-Point Protocol (PPP) network interface and a VPN tunnel interface with the value of the "IF_TYPE_PPP" Network Driver Interface Specification (NDIS) network interface type.
To differentiate between a PPP interface and a tunnel interface, use a RASENTRY data structure. To use a RASENTRY data structure to obtain the remote access interface type, follow these steps:
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
The ifType value is used to store the NDIS network interface type. Examples of network interface types include the following:
The Internet Assigned Numbers Authority (IANA) has defined and standardized the values of the different NDIS network interface types. The IANA standard includes the following type definitions.
By default, when the remote access service creates a PPP network interface or a VPN tunnel interface in Windows Vista, both interface types are registered in the network stack. This occurs by using the IF_TYPE_PPP value. Functions that use the ifType value return the same ifType value for both a PPP interface and a tunnel interface.
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Examples of functions that use the ifType value include the following:
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Article ID: 928906 - Last Review: January 16, 2015 - Revision: 1.0