Turning on Private Marketplace
If you are working on the marketplace configuration and do not want to allow public access, you can turn the public facing option off so its private to only users who have a valid login with user and pw.
Look for this feature in the admin Settings > General and scroll to the bottom to find this setting. Set as disabled if you want to have your marketplace private and enabled to keep it public.
When the site is set to private, guests will see the following: