Find the SharePoint application pool identity and port

Create a list of web applications that are going to be shared through the Docs service.
  1. Open Windows Internet Information Services (IIS) Manager.
    Record any additional port numbers that are assigned if a web application was extended to create alternate access mappings.
  2. Find the Application Pool identity in the Application Pools list view or in SharePoint Central Administration > Security > Configure service accounts.
    In most instances, for Kerberos constrained delegation (KCD) to work properly, the application pool identity user must be the same for all application pools whose applications will be accessed by the Docs service. This means you cannot have different application pools running under different users.
  3. In SharePoint Central Administration, on the Web Applications tab, find the port for each of the web applications listed. Look in the Alternate Access Mappings view as necessary.
Create Service Principal Names.