Port forwarding

Hi All,
I’m new to haproxy and want to confirm some basic functions.
Currently I port forward my mail server ports on my router to the internal mail server.
My static ip xx.yyy.127.21 port 25 to port 25
Haproxy server

What I want to know is do I remove the port forward from my router and use binding on the haproxy box.
Or do I leave the port forwarding on the router and change the internal forward to the haproxy box?
xx.yyy.127.21 port 25 to instead of the mail server.

I’m using haproxy to allow multiple future websites to share my single static IP.