Accessing internal server using external ip address from internal network

RouterOS Beginner Basics
1

Hi,

so we have a NAS server connected to a mikrotik router, several ports were opened in mikrotik router for this NAS so it would be accessible using external IP address - that works fine, the NAS is accessible from the external IP address from external networks.

This external router ip address is binded to a subdomain. Opening the subdomain in a browser using external network works fine, but if you try to open this same URL inside the network where the server is, then it doesn’t work. Then it only works using internal IP address.

Anything I should be aware of to make this work? So that this external ip call from inside the network would work?

2

You have 2 options:
1 - Hairpin NAT (https://wiki.mikrotik.com/wiki/Hairpin_NAT) - basically, it would translate external address to internal address of the server when accessed from internal network.
2 - Use static DNS in router so that the domain name will resolve to internal address when called from internal network.