Adding Another Domain After Activating an SSL Certificate

Once an SSL certificate has been issued and activated, it doesn't mean your work is done. If you need to add another domain, the process can be straightforward or more involved, depending on the type of SSL certificate you have. This guide will help you understand the options and steps involved in adding a new domain to your existing SSL certificate.

Understanding Your SSL Certificate Type

There are several types of SSL certificates, each with its own set of rules and limitations regarding domain addition. Let's look at each type in detail:

Single-Domain SSL Certificate

A single-domain SSL certificate is the most basic and covers only one domain name. If you have such a certificate and need to add another domain, you won't be able to do so without reissuing the certificate.

Steps:

Contact your Certificate Authority (CA) to request a new single-domain certificate for the additional domain. Follow the domain validation process for the new domain. Install the new certificate on your web server.

While this might seem like a hassle, it's the only option available if you have a single-domain certificate.

Multi-Domain SAN Certificate

Also known as a Subject Alternative Name (SAN) certificate, a multi-domain certificate can cover multiple domains under a single SSL certificate. This is a more flexible option and can be especially useful if you manage multiple sites.

For a multi-domain SAN certificate, you may be able to add additional domains during the reissue process. However, this depends on your CA's policies.

Steps:

Contact your CA to request a certificate reissue with the new domain included. If your CA allows, you might be able to add the new domain during the reissue process. Follow any additional steps required for domain validation, if necessary. Install the new, reissued certificate on your web server.

Wildcard SSL Certificate

A wildcard SSL certificate, denoted with a '*', covers all subdomains of a primary domain. For example, * would cover all subdomains like and

While a wildcard SSL certificate is highly flexible, it does have its limits. You cannot add completely different domains with a wildcard certificate, but you can extend coverage to additional subdomains under the same primary domain.

Steps:

Contact your CA to reissue the wildcard certificate with the additional subdomain included. Follow the domain validation process if necessary. Install the new, reissued certificate on your web server.

In all cases, be sure to review the specific instructions and policies provided by your SSL certificate provider for the most accurate guidance.

The Importance of a Digital Signature

It's worth noting that an X.509 certificate is a digitally signed document. Any changes, even the addition of a new domain, would invalidate the signature. Therefore, you'll generally need to request a new certificate with the added domain.

If you're not using a free certificate authority like Let's Encrypt, you may incur costs for the new certificate. However, you can always try explaining the situation to the CA, as they may be more understanding if it's due to a simple oversight on your part.

In conclusion, adding another domain after a SSL certificate has been issued and activated is possible, but the process can vary depending on the type of certificate you have. Always ensure you follow the steps provided by your CA for the smoothest experience.