title: 403.7 IIS 7.5 SSL client certificate authentication issue
body: <p>I am testing a web service with an external partner using 2 way SSL under IIS 7.5.  I am requiring SSL, requiring a client cert, and using one to one mapping to authenticate to a domain account.  I have configured everything and it works fine on our network (I am able to provide a client cert, get authenticated and invoke the service from browser and test harness).
  From outside of our network (in most cases, see below), I am getting a 403.7 error.  I have gone through the machine level certificate store and made sure the certificates and CAs are trusted.
  Here's the weird thing.  I obtained a Type I cert to test from home (and got 403.7 like our intended partner is).  So I setup Fiddler to debug SSL and send my certificate, and this <em>works</em> for some reason.  I setup a test harness to pass the exact same certificate, and got 403.7.  I test in my browser (IE 9), don't get a prompt for a client cert, and get 403.7.<br>
  Any help appreciated.
  Bill</p>