Fax Port Access Levels

The Fax Service Client API allows your application to query and modify fax port configuration data.

In the Win32 Environment

To allow users access to a port's configuration data, a fax client application must specify the correct fax port access level when it calls the FaxOpenPort function. FaxOpenPort returns a fax port handle and opens the port according to the specified access level. The application can request one of the following values, depending on the requirements and permissions of the user.

PORT_OPEN_QUERYPort access level required to query fax port information with calls to the FaxGetPort, FaxEnumPorts and FaxGetDeviceStatus functions.
PORT_OPEN_MODIFYPort access level required to modify the configuration of a fax port with a call to the FaxSetPort function. This access level implicitly grants the access rights associated with the PORT_OPEN_QUERY access level.


In addition to requiring that a port be opened with the appropriate access level, the fax service also requires that users have appropriate access rights when querying and modifying port data. To obtain a fax port handle and to query port data, a user must have FAX_PORT_QUERY permission. To modify port data, a user must have FAX_PORT_SET permission. For more information, see Fax Client User Access Rights and Fax Device Management.

To query a user's access rights, a fax client application can call the FaxAccessCheck function. You can use the fax service administration application, a Microsoft Management Console (MMC) snap-in component, to modify port access privileges for users.

In the COM Implementation Environment

Before your application calls a method that modifies a FaxPort property, you can call the IFaxPort::get_CanModify method (retrieve the CanModify property of the FaxPort object in Microsoft Visual Basic) to ensure that the client has access to modify the port's configuration. For more information, see Fax Device Management.



Build date: 5/5/2012

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