Normally we turn on the DNS debugging to find out the source client IP addresses and the queried records. And, here is the script that will covert the DNS Debug Log file into a more flexible csv format, though you will have to rename the file to .csv if needed. New lines, whitespace and header information will be ignored during conversion. The script supports DNS Debug log of Server 2012, 2016 and 2019 (not tested on Server 2008 and if you can do it successfully, please comment). This script should not be run on Domain Controllers/DNS Servers as it consumes certain amount of processing power.
Use the following command to start conversion.
.\Parse_DNS_Debug_Log_v1.1.ps1 -Sample_DNS_Debug.txt
You can download my script here.
Can you post an example snippet of what the parsed text looks like?
It would be the csv file in the format of DateTime,SourceIP,FQDN