shell:$ nslookup -timeout=2 -retry=1 'b.ns.facebook.com' Server: 75.98.161.224 Address: 75.98.161.224#53 Non-authoritative answer: Name: b.ns.facebook.com Address: 129.134.31.12 Name: b.ns.facebook.com Address: 2a03:2880:f0fd:c:face:b00c:0:35