IIS - NTFS Permissions

Dear

  I have a website that should be able to read reports on the server.

  I have turned on Windows Authentication and would like the reports on the
file server to be accessed by the Client Windows Account.

  This way, I can put NTFS permissions on the folder and have access to the logins that are allowed to read reports or not (from my website).

  I have this in my web.config:
  <Authentication mode = "windows" />
  <Identity impersonate = "false" />

  Now my question is what the right settings are for this?

  Which application pool (ApplicationPoolIdentity, Local Service, Local System, NetworkService)?
  Only enable Windows Authentication?
  Are there other settings I overlook to do this?

  Thanks for the help ...

  Grtz
  M81