Robtex

Up: 27.131.12.0/23
Can't show all results, try to descend to a more specific CIDR
Down left: 27.131.13.0/25
Down right: 27.131.13.128/25
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
27.131.13.2	A+PTR	dns2.dfnbd.net
27.131.13.2	A	ns1.bdmatrix.net
27.131.13.2	A	mail.bdmatrix.net
27.131.13.3	PTR	27.131.13-3-servers.dfnbd.net
27.131.13.5	PTR	27.131.13-5-noc.dfnbd.net
27.131.13.6	PTR	27.131.13-6-servers.dfnbd.net
27.131.13.7	PTR	27.131.13-7-noc.dfnbd.net
27.131.13.9	PTR	27.131.13-9-servers.dfnbd.net
27.131.13.10	PTR	27.131.13-10-servers.dfnbd.net
27.131.13.13	PTR	27.131.13-13-noc.dfnbd.net
27.131.13.26	PTR	27.131.13-26-servers.dfnbd.net
27.131.13.38	PTR	27.131.13-38-servers.dfnbd.net
27.131.13.106	PTR	27.131.13-106-servers.dfnbd.net
27.131.13.110	PTR	27.131.13-110-servers.dfnbd.net