You misunderstand: the sending port (here 64027) has nothing to do with the listened port (8000, 9000, ?).
(you may find useful to read about how networking works)
Anyway: you don’t care the sending port, only the listened port on the destination machine.
The easiest way is to listen the same port (8000) on all machines, that’s generally what I do.
If you cannot do that, and you want a system that runs without configuration, every machine should add its listened port (“callback port”) to the message it sends.