shell:$ nslookup -timeout=2 -retry=1 'mqtt.c10r.facebook.com'
Server:		127.0.0.53
Address:	127.0.0.53#53

Non-authoritative answer:
Name:	mqtt.c10r.facebook.com
Address: 31.13.80.5
Name:	mqtt.c10r.facebook.com
Address: 2a03:2880:f00e:5:face:b00c:0:8e