$ dig NS outlook.com ; <<>> DiG 9.9.3-rpz2+rl.13214.22-P2-Debian-1:9.9.3.dfsg.P2-4 <<>> NS outlook.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 8538 ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;outlook.com. IN NS ;; Query time: 28 msec ;; SERVER: 10.51.20.100#53(10.51.20.100) ;; WHEN: Fri Nov 22 09:58:48 EST 2013 ;; MSG SIZE rcvd: 40
https://news.ycombinator.com/item?id=6778272