Robtex

Up: 12.129.16.0/23
Can't show all results, try to descend to a more specific CIDR
Down left: 12.129.17.0/25
Down right: 12.129.17.128/25
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
12.129.17.25	PTR	ops.zillow.com
12.129.17.25	A	iamtoodumbtosetupdns.25.17.129.12.hitfarm.com
12.129.17.25	A	*.iamtoodumbtosetupdns.25.17.129.12.hitfarm.com
12.129.17.39	PTR	mx2.zillow.com
12.129.17.40	PTR	message.zillow.com
12.129.17.99	PTR	tid.zillow.com
12.129.17.108	A	zillow.ie
12.129.17.108	A	zillow.hu
12.129.17.108	A	zillow.co.at
12.129.17.111	PTR	image.zillow.com
12.129.17.112	PTR	zestile1.zillow.com
12.129.17.113	PTR	zestile2.zillow.com
12.129.17.115	PTR	movie.zillow.com
12.129.17.118	PTR	static2.zillow.com
12.129.17.180	PTR	mx1.zillowmail.com