I am port-forwarding ports 80 and 443 to a raspberry pi web server
When I am outside of my network, I can do this: http://my.domain.com
and it forwards correctly to the raspberry pi.
When I am inside of my network, the above does not work.
I did have the pi listed in the static leases. But there was no way to resolve my.domain.com directly (I could get to pi.my.domain.com but not to the actual domain itself.)
I added my.domain.com to the hostnames and pointed it to the hostname of the raspberry pi.