How to Obtain and Install a Wildcard SSL Certificate for Use in IIS on Windows

This guide will walk you through the steps of acquiring a wildcard SSL certificate from an online certificate authority (CA) and installing it on a Windows computer to use with Internet Information Services (IIS).

  1. Choosing a Certificate Authority:
    Start by selecting a reputable online CA that offers wildcard SSL certificates. Consider CAs like Let's Encrypt, DigiCert, GoDaddy, or Comodo.
  2. Generating a Certificate Signing Request (CSR):
    On your Windows server, open the IIS Manager, navigate to the server node and open 'Server Certificates'. Click 'Create Certificate Request', fill in the necessary information, and specify your domain in wildcard format (e.g., * as the 'Common Name'. Save the CSR file.
  3. Purchasing the Wildcard SSL Certificate:
    Go to the CA’s website, choose a wildcard SSL certificate, and proceed with the purchase. You will need to provide the CSR file and complete any required validation steps, such as email validation and domain ownership confirmation.
  4. Receiving and Preparing the Certificate:
    After the CA verifies your details, they will issue the SSL certificate, typically sent via email. Download the certificate and any intermediate certificates provided.
  5. Installing the SSL Certificate in IIS:
    Back in IIS Manager, under 'Server Certificates', select 'Complete Certificate Request'. Locate the downloaded certificate file, name the certificate, and choose a certificate store. Finish the installation.
  6. Binding the SSL Certificate to Your Website:
    In IIS Manager, find your site and open 'Bindings'. Add a new binding or modify an existing one, selecting 'https' as the type and your new wildcard SSL certificate from the dropdown. Finalize the binding.
  7. Testing the Configuration:
    Verify your setup by accessing your site using 'https' across various subdomains. Look out for any security warnings or errors in the browser.
  8. Maintenance and Renewal:
    Keep an eye on the certificate’s expiry date and plan to renew it before it expires to prevent any service interruptions.

    Securing multiple subdomains on a Windows server running IIS is streamlined with a wildcard SSL certificate. Following these steps ensures a secure, unified approach to SSL certification for your domain.

    Note: Adherence to SSL/TLS security best practices is crucial. Stay updated with your CA's announcements and follow the latest security guidelines.