Since some time I recognized that each night between 4:00 and 5:00 am my pihole registers a large number of queries (~800) from one single client in my network.
The client is my webserver hosting 3 websites based on Wordpress.
Checking the log, the webserver queries many times its own name, but also a large number of domains unkown to me.
This happens every night at about the same time.
I checked my webserver for open ports (http and https for the websites and ssh internally) and for malware and couldn't find a hint.
I am a bit puzzled what is happening there and where to look further.
It would be great, if anyone would have an idea or a hint.
Thanks!!