The title is a bit of a mouthful, but I’ve recently encountered a situation where I had multiple SSL certificates I wanted bound to two different domains being hosted on the same server with the same IP address.

Using IIS’s Internet Information Services Manager UI application in IIS 7 (not sure if this applies to newer versions), you can assign a binding for an SSL certificate to port 443, but you can only enter an IP address and not the host-header information:

In order to accomplish this, you have to use command line tools. Below is a great resource I found that helped me solve this problem. I’ll pull out the most relevant command:

https://blogs.iis.net/thomad/ssl-certificates-on-sites-with-host-headers

appcmd set site /site.name:”MySubDomainSite” /+bindings.[protocol=’https’,bindingInformation=’*:443:mysubdomain.mysite.com’]

In this example, “MySubDomainSite” is the site you have defined in IIS for the subdomain (or domain) where you are trying to assign the second certificate.