Hi @HanWa! I created a new topic for your question. Do you also use Super Wifi repeater(s) or different kind(s) of repeaters? Do you experience any (connection)problems or are you just wondering what the debug messages mean and why they occur?

Thanks for your reaction,

i am using 3 experia repeaters connected to ethernet, The reason for my question is twofold: reguarly i am disconnected from internet, wifi still functioning. Looking in the log on the modem i see the debug messages every minute.

Hi @HanWa! Ik took some time before I received an answer. The notification seems to be normal. If you change ‘Severity’ setting for ‘Operator Logs’ from 'Debug or higher' to 'Info or higher'. Then these DNS messages will no longer be displayed. 

If you are disconnected from (wired) internet while WiFi is still working, there is something wrong with the ethernet cable or with (one of the) LAN outputs. Are you sure WiFi still works if you don't have an internet connection? Isn't only the WiFi symbol visible? 
How do the lights on your modem light up when you're disconnected from the internet?