Only one device with Android (SM-G390F, Android 7.0, G390FXXU2ARA1, 3.18.14-12962328) at my home stopped connecting to Internet through my WiFi router with the message "internet may not be available" and an exclamation mark on the WiFi sign. (Whereas older non-updated Android devices, GNU/Linux and iOS devices work.)
If I examine the current network configuration with
ip a in a Terminal in the device, it has got the correct IP address, but pinging the router (
ping 220.127.116.11) looses all pings... (
ip ro showed a route to this network, but no default route -- but that shouldn't have affected the pinging of the router anyway.)
The WiFi router is an ASUS one, and for this device, in the log, it prints several times (not more than 10; the repetition is only for this device):
udhcpd: sending OFFER of 192.168.1.8
udhcpd: sending ACK to 192.168.1.8
The DNS servers from the DHCP configuration seem to be working well (as tested from other connected devices).
Changing the advanced settings from DHCP to manual does not help. And it is quite strange that this device used to work with this WiFi router all the time before a couple of weeks ago... Nothing has been changed.