a228.sub72.net78.udm.net passed me a porn referrer address. I do not tolerate referrer spam on my site, so I looked them up.
Observation:
a228.sub72.net78.udm.net 78.85.72.228
Pattern:
Fourth, 85, third, then first octet from the host name. It is essentially a reversed ip, except they omit the second octet, the 85.
Research:
sub182.net71.udm.net 62.109.26.122
sub214.net71.udm.net 62.109.27.150
blago.Udm.net 78.85.0.6
Security.udm.net 78.85.0.25
a8.sub0.net78.udm.net 78.85.0.8
d1.sub4.net78.udm.net 78.85.4.1
d236.sub4.net78.udm.net 78.85.4.236
a184.sub8.net78.udm.net 78.85.8.184
a99.sub8.net78.udm.net 78.85.8.99
a1.sub9.net78.udm.net 78.85.9.1
a218.sub12.net78.udm.net 78.85.12.218
a140.sub14.net78.udm.net 78.85.14.140
a188.sub27.net78.udm.net 78.85.27.188
a1.sub28.net78.udm.net 78.85.28.1
a237.sub29.net78.udm.net 78.85.29.237
a16.sub34.net78.udm.net 78.85.34.16
a222.sub35.net78.udm.net 78.85.35.222
a16.sub38.net78.udm.net 78.85.38.16
a181.sub38.net78.udm.net 78.85.38.181
a247.sub48.net78.udm.net 78.85.48.247
a104.sub64.net78.udm.net 78.85.64.104
a179.sub65.net78.udm.net 78.85.65.179
a83.sub69.net78.udm.net 78.85.69.83
a1.sub72.net78.udm.net 78.85.72.1
a156.sub72.net78.udm.net 78.85.72.156
a220.sub72.net78.udm.net 78.85.72.220
a228.sub72.net78.udm.net 78.85.72.228
a1.sub73.net78.udm.net 78.85.73.1
a3.sub73.net78.udm.net 78.85.73.3
a48.sub73.net78.udm.net 78.85.73.48
a66.sub73.net78.udm.net 78.85.73.66
a198.sub73.net78.udm.net 78.85.73.198
a205.sub73.net78.udm.net 78.85.73.205
a41.sub80.net78.udm.net 78.85.80.41
a252.sub137.net78.udm.net 78.85.137.252
a25.sub139.net78.udm.net 78.85.139.25
a33.sub146.net78.udm.net 78.85.146.33
a142.sub16.net78.udm.net 78.85.16.142
a19.sub160.net78.udm.net 78.85.160.19
a113.sub165.net78.udm.net 78.85.165.113
a7.sub176.net78.udm.net 78.85.176.7
a0.sub179.net78.udm.net 78.85.179.0
a86.sub179.net78.udm.net 78.85.179.86
a1.sub180.net78.udm.net 78.85.180.1
a107.sub181.net78.udm.net 78.85.181.107
a1.sub195.net78.udm.net 78.85.195.1
a19.sub210.net78.udm.net 78.85.210.19
a31.sub211.net78.udm.net 78.85.211.31
a0.sub240.net78.udm.net 78.85.240.0
A52.sub247.net78.udm.net 78.85.247.52
a25.sub248.net78.udm.net 78.85.248.25
a107.sub255.net78.udm.net 78.85.255.107