When I would try to access my domain from within my local network, I would be redirected to my router's settings like I was entering 192.168.1.1 to configure my router. What I did was utilize a feature of my router called "DNS Server" which allowed me to make a list of domains and redirect them to my server's local IP address. For example, I wanted to access zandooy.com from within my network so I added zandooy.com with 192.168.1.21 to the DNS Server list in my router. Now when I browse to http://zandooy.com
it redirects to my server inside my LAN located at 192.168.1.21.
Hope this helps,