When creating a multisite and adding multiple subsites with a subdomain multisite, you’ll find that with each new subdomain you add, the subdomain would need to be added to your WP Engine User Portal as well, under Domains. For just a few subdomains this isn’t so bad, but it’s definitely understandable that this process could be frustrating for users with a large number of subdomains.
For that reason, we have an option called “Domain Wildcarding,” which when enabled will automatically assign anything that comes before your root domain (for example anything.domain.com) to your multisite WordPress install with WP Engine. Simply reach out to Support from your User Portal and we will be glad to help enable this setting for you.
If you are using a custom domain as your multisite’s primary domain (for example domain.com), subdomain subsites will be created as a subdomain of that primary domain (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. Though every DNS provider is different, this record will usually look like “*.domain.com” in your DNS settings. We recommend setting this record as a CNAME to your install.wpengine.com domain, as outlined here. If you have questions regarding how to set up this record, we recommend contacting your DNS provider for further help.
Please note: If you are using other subdomains of your multisite’s primary domain on other WP Engine installs, we do not recommend enabling Domain Wildcarding. Since Domain Wildcarding will assign any subdomain of your primary domain to your multisite install, you may run into issues using another subdomain on a separate install. If you plan to have a subdomain in use on another install, we do recommend adding each subdomain of your multisite to your Domains list in the User Portal to help ensure things are kept separate, rather than using Domain Wildcarding.