Fetchmail Concept

I have 2 servers running Red Hat 7.2. I would like to test my 2 servers to use fetchmail. One server I have created the DNS (BIND) server as domain1.com and the other one as domain2.edu. Assume that domain1.com is for ISP and domain2.edu as local domain. What are the concepts and steps that I have to follow to configure both in ISP and local? Thank you so much for your assistance.