porter's lodge

noun2

1. •
   A building for the porter(s) near the gate of a castle, college, etc., (historical) formerly used as a place of punishment for the staff.

   • The keys... were on Saturday stolen from the porter's lodge. — 1819
2. •
   (UK, Canada) An equivalent room near the gate of a college, chiefly used as a mailroom.

   • [H]e walked across Hawthorn Tree Court on his way to the porter's lodge. […] At the lodge he cleared his pigeon-hole. — 1991