Access ODK Central within LAN

I have successfully installed ODK central and docker ps shows all processes are up. During the configuration, I set the domain to a subdomain that the network team created. I need prove the accessibility of central within LAN before I request for publication of the sub domain. And in the long run, I’ll desire accessing the central instance by LAN name and by the sub-domain yet to be published. I used the default let’s encrypt during installation and sources reveal that let’s encrypt only works with already published domains. How can I go about this?

@danbjoseph you want to look at this?