Is there a setting somewhere to allow me to prevent unregistered users from logging tickets?

If you are using the DotNetNuke version, you simply set the Visibility of the module to Registered users only.

Greetings
I want to use the mentioned option using ASP.NET version of the site. How do I do that?
Thank you in advance.

Anyway.. I managed it adding this code below in the web.config
<authentication mode="Forms" />
and
<location path="Login.aspx">
<system.web>
<authorization>
<allow users="?"/>
</authorization>
</system.web>
</location>
<location path="Default.aspx">
<system.web>
<authorization>
<deny users="?" />
</authorization>
</system.web>
</location>

Anyway.. I managed it adding this code below in the web.config

That should work.