So I created a Single Web Application: rootsite.contoso.com with a Root Site Collection. I set the Authentication in the Web App to use Kerberos and then Set the SPN for the AppPool account running the Web App with HTTP/rootsite.contoso.com and HTTP/rootsite.

Checking for Kerberos via Fiddler and it works, wonderful. However, now it seams I have to Add Each Host-Named Site Collection to the same Service Account running the AppPool in order for these sites to render via Kerberos.

Is this correct? I'm concerned first that it's a maintenance issue, and second, that the list of SPN values will get out of hand.

1 Answer 1


Yes, you need an SPN for every hostname site collection URL. Technically, we need a SPN for all the url which leads us to get the web application.

Number of SPN depends upon number HNSC collections, tough job.

  • So, I could conceivably overrun the hard coded 8k limit ?
    – Bismarck
    Commented Apr 29, 2016 at 20:20
  • 8K limit, which limit we are talking about?
    – Waqas Sarwar MVP
    Commented Apr 29, 2016 at 20:21
  • I may be wrong in this particular area, I don't think its Token Bloat but I believe there is a limit to the multi-string value. How is MS doing this in the Cloud?
    – Bismarck
    Commented Apr 29, 2016 at 20:32

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