Robtex

Up: 168.136.0.0/15
Can't show all results, try to descend to a more specific CIDR
Down left: 168.137.0.0/17
Down right: 168.137.128.0/17
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
168.137.0.16	A+PTR	cc02.hrblock.com
168.137.0.136	A	vpromps.hrblock.com
168.137.0.150	A	hrbbc02.hrblock.com
168.137.0.200	A	vpnclient.hrblock.com
168.137.1.0	A	168.137.130-static.reverse.softlayer.com
168.137.1.1	A	168.137.111-static.reverse.softlayer.com
168.137.10.222	A	hrblock.ie
168.137.16.205	A+PTR	efsportal.hrblock.com
168.137.16.206	A+PTR	efsqa.hrblock.com
168.137.16.207	A	efsdev.hrblock.com
168.137.32.13	A+PTR	ecom.es.hrblock.com
168.137.32.14	PTR	tpadmin.es.hrblock.com
168.137.32.15	A	efile.es.hrblock.com
168.137.32.16	A	m.hrblock.com
168.137.32.20	A	mail21.hrblock.com
168.137.32.50	A	taxofferings.com
168.137.33.17	A	taxofferings.com
168.137.33.17	A	ftp.taxcut.com
168.137.33.17	A	hrbtax.com
168.137.35.16	A+PTR	static.es.hrblock.com
168.137.35.17	A+PTR	hrblockfoundation.org
168.137.35.17	A	blockfoundation.org
168.137.36.240	A	ns4.hrblock.com
168.137.36.241	A+PTR	ns6.hrblock.com
168.137.41.6	A+PTR	ns4.hrblock.com
168.137.41.6	PTR	hixtest2.hrblock.com
168.137.41.7	A	ns6.hrblock.com
168.137.44.35	A	mail.newriverinnovation.com
168.137.100.12	A+PTR	tpmailinfoqa.hrblock.com
168.137.100.13	A+PTR	zcsproxy.hrblock.com
168.137.100.14	A	myvpn.hrblock.com
168.137.100.15	A	ra1.hrblock.com
168.137.102.9	A+PTR	ebpm.hrblock.com
168.137.102.15	A	services.hrblock.com
168.137.102.16	A	apistaging.hrblock.com
168.137.102.16	A	puslstaging.hrblock.com
168.137.102.165	A	lnpidp.hrblock.com
168.137.103.11	A+PTR	myblockqa.hrblock.net
168.137.103.12	A+PTR	amqa.hrblock.net
168.137.103.15	A	tstmefapp04.hrblock.net
168.137.103.16	A	tstmefapp05.hrblock.net
168.137.104.10	PTR	lnpiam.hrblock.com
168.137.104.11	A	lnpidp.hrblock.com