My webserver (Debian Bullseye, Apache2) is serving about 50 (small) websites spread over 16 ip addresses. I just noticed that on one of the ip addresses, since the beginning of this month traffic has gone up from an average of 3k/s to an average of 500k/s.
This ip address serves about 8 different domains. Checking the apache logs of these domains, I don't see anything out of the ordinary.
How can I check what is causing this traffic? I tried tcpdump:
tcpdump -i eno1 -v src <ip address>
but don't really understand its ouput so what could be causing the high traffic.
Thanks in advance for your help!