Ever since I updated from Ubuntu/Yakkety to Zesty, my apt-get(1) would sit and wait a while before doing actual work:
dns apt ubuntu
While debugging a problem with EDNS records, I wanted to get some cache info from the PowerDNS pdns-recursor. rec_control dump-cache should supply it, but I did not see it.
powerdns systemd tmpfs dns
A few days ago, the Scapy project was brought to my attention.
python snippet scapy dns