I have found that mDNS can also assist here to make the devices no longer require a reserved DHCP entry.
I used to set up my devices such as my Xiaomi Gateway, and Sonoff modules with a fixed IP address which was accomplished by setting up DHCP IP reservations in my DHCP server.
Now instead I enabled mDNS support and advise OH of there mDNS address and use that for web access also so no need for them to await for DNS.
It does bring an interesting point up though. If for some reason a device such as a sonoff module powers up prior to the DHCP server being available even with mDNS configured it still needs an IPv4 addrwess (its what I still primarily use), as I do not want to go to setting static IP addresses on every sonoff and managing them, I am trying to move away more from manual address management and more towards zero config then the Sonoff will evbentually timeout and give itself an 169 address. So should I therefore also add a secondary address on the OH server in the 169 address subnet so that it can talk to these early devices?
Anyone have any thoughts on this, best practises?
I am off to do some research on the subject to see what others have come up with.