The sign-in name is one of the individual settings of a user account that can be configured on the Communicationstab of Propertiesfor the user, if the individual user has been enabled for Office Communications Server 2007 R2. The sign-in name specifies the Session Initiation Protocol (SIP) address that is registered for the user and is used to route messages to and from the user. The sign-in name is in the form "sip:user@domain" and it must be unique.

To change the sign-in name for a specific user account

  1. Open the Office Communications Server 2007 R2 snap-in.

  2. In the console tree, expand the forest node, and then navigate to the Standard Edition server or Enterprise pool that contains the user account that you want to configure.

  3. Expand the pool name for the Enterprise pool or the Standard Edition server, and then expand Users.

  4. In the details pane, right-click the user account name, and then click Properties.

  5. On the Communicationstab, in Sign-in name, do the following:

    • Specify the sign-in name (such as sip:usera).

    • In the drop-down list box, select the domain (such as