Enable contact lookup by phone number

To allow users in your environment to lookup contacts using their phone number, use the Microsoft Active Directory schema MMC snap-in to index and enable ANR for the applicable phone attributes.
The phone number must be in a supported format. For a list of supported formats, see Searching for users by phone number.
  1. Click the Attributes folder in the snap-in.
  2. In the right panel, right-click the desired attribute, and then click Properties.
  3. Select the Index this attribute check box.
  4. Select the Ambiguous Name Resolution (ANR) check box.
  5. Click OK.
  6. If you have multiple phone attributes, repeat steps 2 to 5 for each attribute.