Robtex

Up: 66.220.152.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 66.220.152.0/23
Down right: 66.220.154.0/23
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
66.220.152.9	A	edge-liverail-shv-09-frc1.facebook.com
66.220.152.10	A	beta-shv-09-frc1.facebook.com
66.220.152.10	A	*.beta.beta.facebook.com
66.220.152.16	A	origincache-shv-04-ash5.fbcdn.net
66.220.152.16	A	instagram-shv-09-frc1.fbcdn.net
66.220.152.16	A	origincache-ash.t.fbcdn.net
66.220.152.17	A	rycpw.com
66.220.152.22	A	edge-z-shv-09-frc1.facebook.com
66.220.152.23	A	edge-z-m-shv-09-frc1.facebook.com
66.220.152.24	A	choubei.com.cn
66.220.152.24	A	bbb40.com
66.220.152.28	A	365bb.com
66.220.152.28	A	tyc1070.com
66.220.152.28	A	383775.com
66.220.152.208	PTR	star-shv-11-ash2.facebook.com
66.220.153.15	A	illhaveanotherbeer.com
66.220.153.35	A	fbplugin.com
66.220.153.36	A	fbplugin.com
66.220.153.74	A	www.smvpn.top
66.220.153.74	A	h558b.com
66.220.153.74	A	q022666.com
66.220.155.10	A	jawsj.com
66.220.155.10	A	76555p.com
66.220.155.12	A	www471919.com
66.220.155.12	A	8899677.com
66.220.155.12	A	175919.com
66.220.155.44	A+PTR	mx.ash2.facebook.com
66.220.155.128	A+PTR	66-220-155-128.outmail.facebook.com
66.220.155.129	A+PTR	66-220-155-129.outmail.facebook.com
66.220.155.130	A+PTR	66-220-155-130.outmail.facebook.com
66.220.155.131	PTR	66-220-155-131.outmail.facebook.com
66.220.155.132	A+PTR	66-220-155-132.mail-mail.facebook.com
66.220.155.132	A	66-220-155-132.outmail.facebook.com
66.220.155.135	PTR	66-220-155-135.mail-mail.facebook.com
66.220.155.135	A	outmail001.ash2.facebook.com
66.220.155.135	A	66-220-155-135.outmail.facebook.com
66.220.155.136	A+PTR	66-220-155-136.mail-mail.facebook.com
66.220.155.136	A	66-220-155-136.outmail.facebook.com
66.220.155.136	A	outmail002.ash2.facebook.com
66.220.155.137	A+PTR	66-220-155-137.mail-mail.facebook.com
66.220.155.138	PTR	66-220-155-138.mail-mail.facebook.com
66.220.155.139	PTR	66-220-155-139.mail-mail.facebook.com
66.220.155.140	A+PTR	66-220-155-140.mail-mail.facebook.com
66.220.155.140	A	66-220-155-140.outmail.facebook.com
66.220.155.141	A+PTR	66-220-155-141.mail-mail.facebook.com
66.220.155.141	A	66-220-155-141.outmail.facebook.com
66.220.155.142	PTR	66-220-155-142.mail-mail.facebook.com
66.220.155.143	PTR	66-220-155-143.mail-mail.facebook.com
66.220.155.144	A+PTR	66-220-155-144.mail-mail.facebook.com
66.220.155.144	A	66-220-155-144.outmail.facebook.com
66.220.155.145	A+PTR	66-220-155-145.mail-mail.facebook.com
66.220.155.145	A	66-220-155-145.outmail.facebook.com
66.220.155.146	PTR	66-220-155-146.mail-mail.facebook.com
66.220.155.147	PTR	66-220-155-147.mail-mail.facebook.com
66.220.155.148	A+PTR	66-220-155-148.mail-mail.facebook.com
66.220.155.148	A	outmail014.ash2.facebook.com
66.220.155.148	A	66-220-155-148.outmail.facebook.com
66.220.155.149	A+PTR	66-220-155-149.mail-mail.facebook.com
66.220.155.150	PTR	66-220-155-150.mail-mail.facebook.com
66.220.155.151	PTR	66-220-155-151.outmail.facebook.com
66.220.155.152	PTR	66-220-155-152.outmail.facebook.com
66.220.155.152	A	66-220-155-152.mail-mail.facebook.com
66.220.155.153	A+PTR	66-220-155-153.mail-mail.facebook.com
66.220.155.153	A	66-220-155-153.outmail.facebook.com
66.220.155.154	A+PTR	66-220-155-154.mail-mail.facebook.com
66.220.155.155	PTR	66-220-155-155.mail-mail.facebook.com
66.220.155.156	A+PTR	66-220-155-156.mail-mail.facebook.com
66.220.155.156	A	66-220-155-156.outmail.facebook.com
66.220.155.157	A+PTR	66-220-155-157.mail-mail.facebook.com
66.220.155.157	A	66-220-155-157.outmail.facebook.com
66.220.155.158	PTR	66-220-155-158.mail-mail.facebook.com
66.220.155.159	PTR	66-220-155-159.outmail.facebook.com
66.220.155.160	A+PTR	66-220-155-160.outcampmail.facebook.com
66.220.155.161	A+PTR	66-220-155-161.outcampmail.facebook.com
66.220.155.161	A	outcampmail002.ash2.facebook.com
66.220.155.162	PTR	66-220-155-162.outcampmail.facebook.com
66.220.155.162	A	outcampmail003.ash2.facebook.com
66.220.155.163	PTR	66-220-155-163.outcampmail.facebook.com
66.220.155.164	A+PTR	66-220-155-164.outcampmail.facebook.com
66.220.155.165	A+PTR	66-220-155-165.outcampmail.facebook.com
66.220.155.165	A	outcampmail006.ash2.facebook.com
66.220.155.166	A+PTR	66-220-155-166.outcampmail.facebook.com
66.220.155.167	PTR	66-220-155-167.outcampmail.facebook.com
66.220.155.168	A+PTR	66-220-155-168.outappmail.facebook.com
66.220.155.169	A+PTR	66-220-155-169.outappmail.facebook.com
66.220.155.170	A+PTR	66-220-155-170.mail-campmail.facebook.com
66.220.155.170	A	66-220-155-170.outappmail.facebook.com
66.220.155.171	PTR	66-220-155-171.mail-campmail.facebook.com
66.220.155.172	A+PTR	66-220-155-172.outappmail.facebook.com
66.220.155.172	A	outappmail005.ash2.facebook.com
66.220.155.172	A	66-220-155-172.mail-campmail.facebook.com
66.220.155.173	PTR	66-220-155-173.mail-campmail.facebook.com
66.220.155.173	A	outappmail006.ash2.facebook.com
66.220.155.174	PTR	66-220-155-174.outappmail.facebook.com
66.220.155.175	PTR	66-220-155-175.outappmail.facebook.com
66.220.155.178	A+PTR	intmgw155178.mxout.facebook.com
66.220.155.179	PTR	intmgw155179.mxout.facebook.com
66.220.155.194	A+PTR	pushnotifs-shv-17-frc1.facebook.com
66.220.155.196	A+PTR	origincache-shv-17-frc1.fbcdn.net
66.220.155.196	A	origincache-pf.t.fbcdn.net
66.220.155.196	A	origincache-frc.t.fbcdn.net
66.220.155.197	A+PTR	snaptu-da-shv-17-frc1.facebook.com
66.220.155.198	PTR	snaptu-za-shv-17-frc1.facebook.com
66.220.155.200	A+PTR	snaptu-service-proxy-shv-17-frc1.facebook.com
66.220.155.224	A+PTR	atlasalpha-shv-07-ash3.facebook.com
66.220.155.228	A	pushnotifs-shv-07-ash3.facebook.com