How to make a domain forward from one port to another?

Question

Domain Name System

I have a domain, for example example.com, and when I go to example.com:12345 instead of 1.2.3.4.5:12345, a person gets to 1.2.3.4.5:23456

(I took the domain, IP and port out of my head, I need exactly the solution)

Answer 1

DNS does not know how to do this, you need a web server (or proxy, load balancer, etc.)