How can you tell if someone is authenticated in Iguana's 6.0 GUI?

That could be tricky since Iguana uses cookies to store user sessions. Cookies are associated with a specific URL - if you are writing your web code in the context of Iguana and you want to piggy back off Iguana’s authentication then you’ll need to be on the same URL.

Is that even possible?

The answer is no - I tried configuring the HTTPS port to use the same port as the Iguana GUI and it doesn’t work since that is only for supporting some legacy usage non translator based HTTP ports which we discourage.

What might be possible is to reverse engineer the login sequence for Iguana so that someone can login and use the Iguana username and password - be a matter of looking at the network tab in the browser debug tools and seeing if that could be replicated.

Actually an easier way to do that would be to authenticate with the log api - if it works then the user has authenticated with a valid username/password combination.