When adding subsites to a subdomain multisite, you’ll find that each new subdomain also needs to be added to the Domains section of your WP Engine User Portal. For just a few subdomains this process isn’t so bad, but it can become frustrating for users with a large number of subdomains.
For that reason, we have an option called “Domain Wildcarding.” When enabled, any subdomain that may come before your root domain (ex. anything.domain.com) is automatically assigned to that Environment’s Domains section. Reach out to Support from your User Portal and we will be glad to enable this setting for you.
Set DNS Records
If you are using a custom domain as your multisite’s primary domain (ex. mycoolsite.com), subdomain subsites will be created as subdomains of that primary domain (ex. subsite.domain.com). For this reason, you will also need to ensure that a DNS record is set up with your DNS provider for each of your subdomains. We recommend setting this record as a CNAME to your [Environment].wpengine.com domain, as outlined in our DNS Best Practices article. If you have questions regarding how to set up this record, we recommend contacting your DNS provider for further help.
Wildcard SSL Recommended
If you are using a single-domain SSL certificate (such as WP Engine’s free Let’s Encrypt certificates) for each subdomain, you will need to add each subdomain manually to the Domains section of your User Portal. To avoid this, we recommend installing a wildcard SSL.
A wildcard SSL will cover all subdomains whether or not they are added to the Domains section, as long as “Domain Wildcarding” is enabled. You can install a RapidSSL wildcard domain-validated (DV) certificate by visiting the SSL section of your User Portal and selecting “Add certificates”.
Please note: If you need specific pages configured in your SSL settings to apply to only one (or a few) of your subdomains, that subdomain will still need to be added separately to the Domains section of the User Portal.
When Is Domain Wildcarding Not Recommended?
If you are using other subdomains of your multisite’s primary domain on separate WP Engine Environments, we do not recommend enabling Domain Wildcarding. Since Domain Wildcarding will assign all subdomains of your primary domain to your multisite Environment, you may run into configuration issues with the subdomains configured for other Environments.
If you plan to have a subdomain in use on another site, we do recommend adding each subdomain separately to the Domains section in the User Portal to ensure each is configured correctly.