Robtex

Up: 64.235.158.0/24
Can't show all results, try to descend to a more specific CIDR
Down left: 64.235.158.0/26
Down right: 64.235.158.64/26
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
64.235.158.10	A+PTR	backup.barracudanetworks.com
64.235.158.11	PTR	wan.nc2.bbs.rdn.cudaops.com
64.235.158.11	A	wan.nc3.bbs.rdn.cudaops.com
64.235.158.12	PTR	wan.nc3.bbs.rdn.cudaops.com
64.235.158.16	PTR	barracuda.com
64.235.158.20	A+PTR	mx.mas.uk.barracudanetworks.com
64.235.158.20	A	mas.uk.barracudanetworks.com
64.235.158.32	PTR	barracuda.com
64.235.158.34	PTR	mail7.ess.uk.barracuda.com
64.235.158.34	A	d203652.a.ess.uk.barracudanetworks.com
64.235.158.34	A	d200123.b.ess.uk.barracudanetworks.com
64.235.158.37	PTR	mail7.ess.uk.barracuda.com
64.235.158.37	A	d200600.o.ess.uk.barracudanetworks.com
64.235.158.37	A	d201258.o.ess.uk.barracudanetworks.com
64.235.158.40	A+PTR	3pmail.ess.uk.barracuda.com
64.235.158.45	A+PTR	8pmail.ess.uk.barracuda.com