A log-rotation script and daemon for dnsmasq.
Simple stuff. Developed on OpenWrt.
Useful for archiving the DNS log file so I can analyse it.
I use it for blocking YouTube advertising. For example, this command will find all the domains used in the DNS history (assuming sufficient history to be useful):
find [storagedir] -type f -exec unzip -p {} ; | grep -i googlevideo | awk '{print $6}' | sort | uniq -c | sort -n
I store the archives on a large USB flash stick attached to the router.