Hi Randall,
It is open to the outside. I only want users who are on our domain to access Portal, but I want some of my applications and layers to be open to everyone (for say an Open Data Portal). I've been looking at the SAML single sign on option, but I thought I had read somewhere that I cannot use built-in logins as well as SAML. I have Field Workers who are not in Active Directory that use applications in the field, and I want them to be able to access as well. Not to mention we have public facing applications in the works as well. If I can do all that with SAML, then I'm in.