No, it's not always a room filled with wires and glowing blue lights. It's probably not even the size of your furnace. The personal email server used by Hillary Rodham Clinton during her time as secretary of state was probably about the size of your office desktop computer and could have been tucked quietly in a corner somewhere.
She's come a long way since 1997, when Clinton's staff bought the then-first lady a copy of the book "E-Mail for Dummies."