When I type in my IP address into a browser, it takes me to one of my sites. I'm sure there is a logic to which site ISPConfig 3 is picking, I think its choosing the first site I made. How can I control which site is the default site that gets shown when the IP address is typed into the browser?
As long as all your sites have the same IP address set, the selection is based on the domain name, so you can create something like 000default.com (the name does not need to be a registered domain name) and upload your default sure there.