DIR645, DNS323 and DNS345 on a home network, Win10
Initially, everything was working well: ISP-supplied modem supported my DNS345, a desktop and a 4-port switch, the switch connected another desktop, a printer and the DNS323.
My ISP upgraded my service and moved their modem, so after the installation, I had to reinstall a DIR645 to replace the functionality previously provided by the ISP modem to provide the 6 ports I needed. However, now the DNS345 is not visible on the network. Internet connectivity to the desktops is good, I can access the DIR645 (192.168.0.1), and the DNS323 is visible and accessible (in Windows but not in a browser). The DNS345 is not and I cannot get to the UI page despite using the IP address displayed on the DNS345 front panel display (which has not changed).
I figure somehow I"m not using the correct IP addresses but I don't know how to discover them since the DIR 645 is not reporting them on the Network Settings page. The DIR645's DHCP Server is enabled, the Host Address is 192.168.0.1, SNM 255.255.255.0 and 3 devices are reported on the Status Page but two of them are inaccessible (the 3rd appears to be the printer). WiFi is disabled. When I used this setup a few months ago, all of the network devices were visible on the Network Settings page.
The odd thing for me is why the DNS323 is working but the DNS345 isn't. I can use the devices connected via the switch but not directly to the DIR645. I've checked and reconnected the device, and power cycled the DNS345 and DIR645.
I'm stuck and don't know where to go from here.