Access the Neighborhood site and click on the Sign In link on the top right-hand side. It will take you to the Sign In portlet. Notice the Create Account link at the bottom of the Sign In portlet which indicates that a guest user can create a new account on the site. Now log in as site administrator user ([email protected] / test123) and go to Control Panel | Portal | Portal Settings.

Now on the portal settings screen, click on Configuration | Authentication. It will open a screen as shown in the following screenshot with the General tab selected, by default.

You can see various configuration options for authentication. Each of them is very important and useful. The option which is of interest to you right now is Allow strangers to create accounts?. Uncheck this option to disable a guest user from creating an account. After that, you should click on the Save button from the right-hand side menu to save the changes.

Now,...