Hum OK, so yep it’s all on the same subnet 192.168.1.0/24.
Yes, PiHole is installed on the HA machine, it’s the rpi. HA is installed through a venv, with different user. I don’t think there’s a problem withe the HA configuration, for me it’s more on the network side.
The thing I’m unable to understand it’s why I can’t reach the ESPhome devices from the pi, and at the same time I can reach everything else (NAS, phone over wifi, laptop on Windows, on linux, etc…)
Only difference I can tell is that ESPhome on ESP8266 boards don’t support IPv6, but I don’t see how it’s affecting ping with v4.
All of this appeared after I switch off wifi for 10mn or so, disconnecting the pi (it’s connected over wifi) and ESPhome devices. Then after switching back wifi, I was able to access HA, but my ESPhome devices were unreachable. It’s from there that I checked ping and stuff (I reprogrammed the ESPhome devices via UART, with no result).
In fact, the windows machine is connected to the router through Ethernet.
Whereas the rpi over WiFi, on 5GHz band. But the ESPhome devices are connected on the 2,4GHz.
After disabling the 5GHz band on the router, thus forcing the rpi on 2,4GHz, everything is back to normal and I can ping every devices from everywhere.
Thanks John, the linked post made me realize that I have the two wifi frequencies enabled on my router.
This is strange, unless you have allocated different IP range, your devices should be discoverable across both bands, unless there is a specific setting in the router that blocks the IP addresses from 1 band to another.
You can enable DHCP in router and try to check again with enabling both bands in router. If you are worried about the RPI ip changing - you can reserve the ip address in router (unless your router does not support it)
I am just saying this since 5GHz significantly improves the connectivity across the devices (including internet)