shell:$ nslookup -timeout=2 -retry=1 'web-darkdata.viber.co'
;; Got SERVFAIL reply from 75.98.161.224, trying next server
;; Got SERVFAIL reply from 69.39.86.5
Server: 69.39.86.5
Address: 69.39.86.5#53
** server can't find web-darkdata.viber.co: SERVFAIL
| 