have bought a secondhand wireless router D-Link DIR 842 C2 and installed OpenWrt. I configured the DHCP and DNS section that running dnsmasq services just like krause did here. In the MoodleBox, I didn't change any of the configuration. Now I can use it in LAN and every device connected to the LAN can access the Moodle website easily (without any configuration to the hosts file on client devices).
Now, my issue is solved!
Thank you very much for your help @Ratna @krause @Nicolas