Robtex

Up: 45.58.64.0/20
Can't show all results, try to descend to a more specific CIDR
Down left: 45.58.72.0/22
Down right: 45.58.76.0/22
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
45.58.74.1	A	dl-client94.dropbox.com
45.58.74.1	A	dl-client23.dropbox.com
45.58.74.1	A	dl-client66.dropbox.com
45.58.74.33	A	dl-client23.dropbox.com
45.58.74.33	A	dl-client66.dropbox.com
45.58.74.33	A	dl-client14.dropbox.com
45.58.74.129	A	dl-client94.dropbox.com
45.58.74.129	A	dl-client86.dropbox.com
45.58.74.129	A	dl-client123.dropbox.com
45.58.74.161	A	dl-client23.dropbox.com
45.58.74.161	A	dl-client66.dropbox.com
45.58.74.161	A	dl-client14.dropbox.com
45.58.75.164	A	block-api-dfw.dropbox-dns.com
45.58.75.165	A	block-www-dfw.dropbox-dns.com
45.58.76.36	PTR	ae12-dfw1-bb02.net.dropbox.com
45.58.76.45	PTR	ae14-dfw3-dr01.net.dropbox.com