Recently was working on an issue with https binding to multiple websites with host headers on IIS 7. Here is the problem:
1) Imported a wild card certificate with a friendly name say "WildCardCert" instead of *.mydomain.com
2) Now assign this "WildCardCert" to test1.mydomain.com https binding on IIS website "test1" using IIS GUI as shown below, and the site works on https protocol.
3) Now assign this "WildCardCert" to test2.mydomain.com https binding on IIS website "test2" using IIS GUI in the same way you did in above step.
you would see the test2 website is down and unavailable. The issue is related to host headers and the tricky thing is that there is no way from the GUI to apply the hostheader while adding the https binding as it is greyed out.
On looking more over the issue, here are the ways to fix it
1) with appcmd tool to rescue. here is the command that will do it.
"C:\Windows\System32\inetsrv>appcmd set site /site.name: "test2" /+bindings.[protocol='https',bindingInformation='*:443:test2.mydomain.com]"
2) Re-import the certificate but with friendly name as "*.mydomain.com" rather than "WildCardCert" and then the host header field will not be greyed out.
More details can be found at these links: Thomad