SSL Multilevel Subdomain Wildcard

I bought a wildcard certificate for *.example.com. Now, I have to secure *.subdomain.example.com. Is it possible to create a sub-certificate for my wildcard-certificate?

If it is, how I can do this?

No, it is not possible. A wildcard inside a name only reflects a single label and the wildcard can only be leftmost. Thus *.*.example.org or www.*.example.org are not possible. And *.example.org will neither match example.org nor www.subdomain.example.org, only subdomain.example.org.

But you can have multiple wildcard names inside the same certificate, that is you can have *.example.org and *.subdomain.example.org inside the same certificate.

It is impossible to secure multi-level subdomains with a single wildcard certificate. If wildcard certificate issued for *.mydomain.tld, so it can secure only first-level subdomains of *.mydomain.com.

To secure your second-level subdomains, you have two choices.

Purchase another wildcard certificate for *.sub1.mydomain.tld. In that case, you need to manage two individual wildcard certificates.

You can go with a multi-domain wildcard certificate, where you can add up to 100 multiple domains or subdomains.

For example,

• *.mydomain.tld
• *.sub1.mydomain.tld
• *.sub2.mydomain.tld
• *.anydomain.com

It will secure your multiple domains and multi-level subdomains and reduce your hassle from multiple certificate management.