Using openHAB my Denon AVR-S740H loses the IP address for connection and it gets replaced with an IPv6 link local address after a power outage. Then it is status offline until I go in and set the IPv4 address or hostname in the thing settings. Any idea why this configuration is not preserved?
IPV6 and IPV4 do not interfere with each other, they are independend. The IPV6 link local address is not replacing an IPV4 address.
Most likely the entity managing the IPV4 adresses in your local network (might be your internet router) assigns dynamic adresses. When the assigned address for your receiver is not being used, e.g. to a power outage of your receiver or you switch off the receiver, the address is being freed up and may be assigned to another device when there is a request for an address.
To solve this issue, identify which device is responsible for address assignation in your network (=acts as DHCP server) and take a look in the settings if there is an option to assign “static” IP addresses or make an adress semi-static after it has been assigned to a specific device. That insures your receiver always will be assigned the same IPV4 address.
So did an experiment and rebooted openhabian PI. If I rebooted it cleared the issue fo the IP is being stored in the config. Seems to be a race condition probably the receiver coming up before the router is up and not getting a IP address. The router is provisioned to assign the same IP to the receiver every time and there is a static host entry in DNS. Both openhabian and receiver have CAT5e cabled connections so they can come up and see the network before the router is fully up. I’ll try setting a true static IP on the receiver and see if that fixes the issue. May also need to set static IP on openhabian.
Would be nice if the discovery retried periodically when the device is in connection fail state.