Robtex

Up: 161.71.8.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 161.71.12.0/23
Down right: 161.71.14.0/23

IP	Type	Hostname
161.71.14.52	A+PTR	mx1-lo3-sp1.mta.salesforce.com
161.71.14.53	A+PTR	mx2-lo3-sp1.mta.salesforce.com
161.71.14.54	A+PTR	mx3-lo3-sp1.mta.salesforce.com
161.71.14.55	A+PTR	mx4-lo3-sp1.mta.salesforce.com
161.71.15.1	A	ns1-lo3.salesforce.com