Robtex

Up: 80.88.16.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 80.88.20.0/23
Down right: 80.88.22.0/23
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
80.88.20.1	PTR	dialin-ip-20-001.ilmenau.net
80.88.20.27	PTR	dialin-ip-20-027.ilmenau.net
80.88.20.170	PTR	dialin-ip-20-170.ilmenau.net
80.88.20.171	PTR	dialin-ip-20-171.ilmenau.net
80.88.20.175	PTR	dialin-ip-20-175.ilmenau.net
80.88.20.177	PTR	dialin-ip-20-177.ilmenau.net
80.88.20.178	PTR	dialin-ip-20-178.ilmenau.net
80.88.20.179	PTR	dialin-ip-20-179.ilmenau.net
80.88.20.194	PTR	dialin-ip-20-194.ilmenau.net
80.88.20.194	A	auspicium.de
80.88.20.217	PTR	dialin-ip-20-217.ilmenau.net
80.88.21.84	A	dialin-ip-21-084.ilmenau.net
80.88.21.112	PTR	dialin-ip-21-112.ilmenau.net
80.88.21.187	PTR	dialin-ip-21-187.ilmenau.net
80.88.21.219	PTR	dialin-ip-21-219.ilmenau.net
80.88.21.242	PTR	dialin-ip-21-242.ilmenau.net
80.88.21.246	A+PTR	dialin-ip-21-246.ilmenau.net
80.88.21.250	PTR	dialin-ip-21-250.ilmenau.net
80.88.22.38	PTR	dialin-ip-22-038.ilmenau.net
80.88.22.109	A	yves-stadelmann.de
80.88.22.115	A	sei-gmbh.dyndns.org
80.88.22.153	PTR	dialin-ip-22-153.ilmenau.net
80.88.22.174	PTR	dialin-ip-22-174.ilmenau.net
80.88.23.2	PTR	dialin-ip-23-002.ilmenau.net
80.88.23.171	PTR	dialin-ip-23-171.ilmenau.net
80.88.23.175	PTR	dialin-ip-23-175.ilmenau.net
80.88.23.175	A	mail2.qsil.com
80.88.23.176	A	vedaevo.de
80.88.23.199	A+PTR	mail2.cs-ilmenau.de
80.88.23.200	A+PTR	mail.ilmcad.de
80.88.23.200	A	mail.ilmcad.eu
80.88.23.220	PTR	dialin-ip-23-220.ilmenau.net
80.88.23.220	A	mail2.etg-ilmenau.de
80.88.23.220	A	mx2.etg-ilmenau.de
80.88.23.228	PTR	dialin-ip-23-228.ilmenau.net
80.88.23.228	A	mail.firmengruppe-fenn.de
80.88.23.249	A	gateway.wwwgroup.de
80.88.23.255	A+PTR	mail1.ra-gilmour.de