Robtex

Up: 74.214.200.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 74.214.200.0/23
Down right: 74.214.202.0/23
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
74.214.200.12	A+PTR	login.postup.com
74.214.200.12	A	login-l3-atx.postup.com
74.214.200.12	A	login.postup.com.akadns.net
74.214.200.13	PTR	api.postup.com
74.214.201.8	A	mail1.postupfbl1.com
74.214.201.8	A	email-postup.com
74.214.201.17	A+PTR	mail1.e.whattoexpect.com
74.214.201.18	A+PTR	mail2.e.whattoexpect.com
74.214.201.19	A+PTR	mail3.e.whattoexpect.com
74.214.201.20	A+PTR	mail4.e.whattoexpect.com
74.214.201.21	A+PTR	mail5.e.whattoexpect.com
74.214.201.22	A+PTR	mail6.e.whattoexpect.com
74.214.201.23	A+PTR	mail7.e.whattoexpect.com
74.214.201.24	A+PTR	mail1.e.everydayhealth.com
74.214.201.25	A+PTR	mail2.e.everydayhealth.com
74.214.201.26	A+PTR	mail3.e.everydayhealth.com
74.214.201.27	A+PTR	mail4.e.everydayhealth.com
74.214.201.28	A+PTR	mail5.e.everydayhealth.com
74.214.201.29	A+PTR	mail6.e.everydayhealth.com
74.214.201.30	A+PTR	mail7.e.everydayhealth.com
74.214.201.31	A+PTR	mail8.e.everydayhealth.com