Multi-Domain SSL/TLS Certificates
A multi-domain SSL certificate is a single certificate that you can use to secure multiple domains (or subdomains if you list them as SANs)
Let's have a look at this example:
John has different websites for each of his businesses and he wants to use HTTPS on all of them without the hassles of managing multiple SSL/TLS certificates. Suppose he wants to secure the following websites:
Naked and www domain
For a single domain, the www is being added automatically, but for multi-domain certificates, this needs to be done manually.
Starting with the Basic subscription he can secure all of these sites by citing them as SANs on a single certificate.
Wildcard SSL/TLS Certificates
With a wildcard SSL certificate, you can secure unlimited subdomains using one certificate at a single level.
Looking back at our example, let's say John has purchased a domain for website1.com, and let's assume that website1.com has multiple sub-domains: login.website1.com, order.website1.com, checkout.website1.com
With a wildcard SSL certificate for *website1.com, John can secure all sub-domains related to website1.com. The asterisk is used to specify one particular level that it can secure, not multiple levels:
You need to be on the Premium subscription in order to issue Wildcard Certificates
Multi-Domain SSL vs Wildcard SSL
| Multi-Domain SSL | SSL Wildcard Certificate |
|---|---|
| A single certificate for multiple domains and subdomains. | A single certificate for an unlimited number of subdomains at a specific level. |
| Limitations on the number of domains covered are defined by the issuing certificate authority. | No limits on the number of subdomains covered. |
| Example: www.website.com, blog.website.com, www.website.org, www.example.com, etc. can all be secured using one certificate. | Example: *.site.com secures every subdomain at that level such as order.site.com, blog.site.com, etc. |
| The different domain names to be secured must be defined and added at the time the certificate is purchased. | Additional subdomains can be added or removed at any time. |
| Available for all levels of validation – DV, OV, and EV. | Available for DV and OV levels of validation only. EV is not an option for wildcard certificates. |