Difference between Domain Controller and ADFS
Muhammad Ayaz Ahmed
Technical PKI (Public Key infrastructure ??? Support Engineer
A Domain Controller holds the actual "Active Directory", i.e., the database of user & computer accounts which are members of the domain.
The ADFS -- Active Directory Federation Server -- does not hold that database, but serves as an intermediary from another/different external domain (or similar), then queries an actual Active Directory Domain Controller to request authentication for users trying to access from that external environment.