Overview

If you would like to secure an environment with multiple sites that have different aliases, you will need a specialized SSL certificate that meets your requirements.

Information

The following alternatives are available presented in online articles with information to achieve the request: 

• Multi-Domain Subject Alternative Names - The Subject Alternative Name field lets you specify additional hostnames (sites, IP addresses, common names, etc.) to be protected by a single SSL Certificate, such as a Multi-Domain (SAN) or Extend Validation Multi-Domain Certificate. This certificate is useful if you have a mix of top-level domains and If you very rarely deploy new online services or websites that need to be secured.
  • Example: You could secure the following domains:

    www.example.com
    www.example2.com
    www.example3.net
    mail.example.net
    dev.example2.net

  • Using Multi-Domain Subject Alternative Names (SAN) can ease the process, find related documentation in the following article: https://www.digicert.com/multi-domain-ssl/
    
    
• Wildcard SSL certificates - A Wildcard SSL certificate allows you to secure multiple subdomains with just one certificate. You can add subdomains without having to redeploy the certificate, which makes it a lot easier. This certificate is useful if you use a lot of subdomains currently and add them frequently. You can get the security of HTTPS without having to shell out a lot of money for separate SSL certificates.
  
  • Example: You could secure the following domains:
    www.example.com
    secure.example.com
    mail.example.com
    
    
• Server Name Indication
  • Another option to consider is the Server Name Indication (SNI) to allow a server to present multiple certificates on the same IP address, this method may be limited to some legacy systems/browsers, find more details in the following articles: http://www.sherweb.com/blog/host-different-ssls-on-one-ip-with-iis-8-sni/ and https://www.globalsign.com/en/blog/what-is-server-name-indication/