Which computer is sending multiple DNS queries?

Question

Domain Name System

Hello.
There is a problem, a large number of DNS requests for the provider come from my server, and the virus scan did not give any results, as antiviruses show the server is clean.
As I understand it, the server can simply redirect such a large number of requests (600 MB in memory and there were a couple of thousand open ports). Tell me how to determine the computer that does this?
If so, then you need to calculate the pest computer :(

Answer 1

and you accidentally DNS server is not open outside, if it is public, then your server itself spams from external requests. First, cover 53 port tcp / udp from the outside

Answer 2

I would start with tcpdump.
See what traffic is coming from, where, where.
90% that there is an answer.