History: By default, IIS websites cannot use the same SSL port (443) for a site using the same IP address. Websites with different IPs can all use port 443. This situation is typical of a standard SSL certificate which is issued to a single host header (ie: secure.website.com). Any other attempt to connect to a site via https through a different host header (ie: www.website.com) causes a certificate error (this is by design).
This becomes an issue when trying to install a wildcard SSL certificate. Wildcard certificates provide the ability to secure all subdomains on the root domain using a single certificate. (*.website.com) examples:
root domain – website.com
subdomains -admin.website.com, shop.website.com,etc
However, after you’ve installed a wildcard certificate and try to set up the subdomain to use SSL port 443, you will receive a Port In Use error. You will not be able to start the subdomain websites with the port set to 443. The IIS MMC (inetmgr.mmc) does not provide a method of resolving this so you must use the command line. (Start -> Run -> cmd)
You need to determine the site identifier of the subdomain you wish to modify. To determine <site identifier> Open IIS MMC, click on Web Sites and view the Identifier number next to the subdomain website. In the following script, replace <site identifier> with the number shown in the IIS MMC and change subdomain.website.com to the subdomain you wish to modify. Run the script with the modifications and you should now be able to browse to https://subdomain.website.com with no error.
cscript.exe c:\inetpub\adminscripts\adsutil.vbs set /w3svc/<site identifer>/SecureBindings “:443:subdomain.website.com”
if you have multiple subdomains, you could create a batch file to run the scripts.
