I had the problem that my pi hole (DNS based ad and spam blocker/privacy solution) was somewhat hammered by DNS requests for rr.openquad.net from my D-Star pi-star, even after I changed every config file I found via 'fgrep -r rr.openquad.net' on the whole system.
I really could not find the reason and kind of gave up and manually added the current IP of rr.openquad.net as entry to /etc/hosts - I guess that reference is compiled in an executable somewhere..