I would like to set up a subdomain multisite network from an installation outside of the document root. From reading the documentation, I understand WordPress isn’t able to do this on its own. However in this thread someone had a configuration that made it possible. Searching didn’t turn up any guides or even a bug ticket. How can I set up my server to make this work?

The website in question is currently one of many separate projects on our development environment. A WordPress installation is already in the root, along with other installations using subdomains sitex.example.com in directories public_html/sitex. Moving these around is unideal because we need to iterate on them with our clients. I imagine in the future there could be simultaneous multisite installations too. Figuring this out would be the most efficient approach for us, however I can use an alternative solution.

When it’s read to go live, I will move this website to a new cPanel account where it can be in the document root. It requires multisite to provide the same theme and plugins for two different websites under the same client while still using the same licences. When going live, they will have two separate top-level domains I will resolve with domain mapping.

So far, the first website is operational under multisite with the second one added as a subdomain. However, because I haven’t set it up yet, trying to navigate to anywhere on the new site returns a 404, as expected.

Our server runs Apache and cPanel. We have access to WHM and SSH. From the information I’ve found, something about domain wildcards needs changing? I can provide additional details if I’ve left out something necessary. What steps do we need to follow in order to get correctly functioning subdomain multisites when outside of the document root?