How can I organize DNS-Forwarding using a router?

Question

Domain Name System

It is necessary to organize the ability to navigate the domain name from the outside through the router to the internal network, conditionally there are two domains s1.domain.com and s2.domain.com, which conditionally both refer to х.х.х.76, it is necessary that when accessing the subdomain s1 went to the internal address х.х.х.1, and when accessing the s2 domain, to the internal address х.х.х.2
What software tools (technologies) are needed for this?

Answer 1

static entries in router dns