Soldier cried briefly, having necked rare port (7)
I believe the answer is:
antwerp
'port' is the definition.
(Belgian port)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for antwerp that I've seen before include "Rent paw out in Belgium" , "Major European port" , "European city" , "9/11 [OLYMPIC VENUE]" , "Belgian port and province" .)