Can you have multiple SSL certificates for one domain?

You can install multiple SSL certificates on a domain, but first a word of caution

A lot of people want to know whether you can install multiple SSL certificates on a single domain. The answer is yes. And there are plenty of websites that do. But before you try to install multiple SSL certificates on one domain there are some things you should know first.

What happens if I have two SSL certificates installed?

When you install two SSL certificates on the same domain it forces the server to decide which one to serve. In some cases the server will send the most recently installed certificate to visiting browsers assuming it’s likely the most secure. In other cases the server may rotate the certificates. It comes down to configuration.

Also keep in mind that various extensions could cause problems with this implementation, for instance is a browser has a plugin that caches SSL certificates having your site continually use different ones could cause issues.

Why would someone install two SSL certificates on the same server?

The most common reasons comes down to replacing expiring certificates. When you renew an SSL certificate, you’re actually replacing the expiring one with a new one for all intents and purposes. Obviously you don’t want to uninstall the expiring certificate first, lest you leave your site unprotected. So most admins will install the new one first and then remove the old one.

There are some other use cases for having two SSL certificates installed on the same host name, but they’re far less common.