Is it possible to extend an existing web application (configured to use classic mode authentication) to use claims authentication? When I try to extend the web app I don't see a option to pick authentication mode in CA...

If the above is not possible, can the existing web app be changed to both claims and win auth? Also the current site uses basic authentication over SSL.

Any kind of help will be appreciated.


1 Answer 1


Claim/classic is controlled by a property UseClaimsAuthentication at the SPWebApplication, so it's not possible to change it by zone.

You can change an existing Classic webapp to run claims (and claims allows you to use windows as one of the authentication providers).

See technet article Migrate from classic-mode to claims-based authentication

  • Thanks I will try that out. I see that the powershell command takes in a zone parameter. Do you know if it is okay to extend a site with win Auth (for example, in the intranet zone) and then change the intranet zone to claims auth?
    – Emon
    Apr 7, 2012 at 21:50
  • 1
    When you change the webapp to claims it'll change for all zones, and you need to add the appropriate AuthenticationProviders to each zone through PowerShell or the UI.You just have to do the first through PowerShell to start the migration Apr 8, 2012 at 7:27

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