Much like his ancestor, Durnan held the adventuring profession in high regard, and welcomed all sorts to his inn. However, he did not abide violence nor other shady activities from his patrons, and was not above using violence himself to enforce his few policies.
The Yawning Portal's taproom contained a well that led directly down into Undermountain, and Durnan the Sixth happily continued the tradition started by his ancestor of lowering willing patrons down the well for ten gold pieces per head.
Despite having been gone for nearly a century, the original Durnan mysteriously returned one day, taking up his old place behind the bar of the Yawning Portal. He paid his descendant a substantial sum to purchase the inn back, allowing him to quietly retire.