Question about server accessing

Hey I want to know what do mean by this “When I accessed vpn.tfbnw.net there’s the Juniper SSL VPN login interface” I mean you found this through public data how did you manage to access it?

What course is this from? What lecture?

Its from your documentation on how to managed to hack facebook?

There was no vulnerabilities. It just showed that tfbnw.net was of interest as a Facebook domain.