shell:$ nslookup -timeout=2 -retry=1 'cm.adgrx.com'
Server:		75.98.161.224
Address:	75.98.161.224#53

Non-authoritative answer:
cm.adgrx.com	canonical name = rtb.adgrx.com.
Name:	rtb.adgrx.com
Address: 44.221.2.112