I've been keeping a desultory eye on the MS 157 ranges for some time. Not sure when it actually happened - probably within the past few weeks - but MS seem to have taken notice of complaints - or just finally got their act together.
I had a handful of IPs tagged as msnbot in my database from a previous DNS scan some time back. The new ranges/sub-ranges (about 100) extend this range but also, in some cases, extend or reduce previously logged ranges. The list I now have, taken from DNS scans of the MS DNS servers, is included below. I think the list is accurate but I cannot guarantee it.
I may have missed a few breaks in the actual bot list IPs (eg there may be a gap in a sequence I missed) but it is essentially correct.
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157.55.2.138 - 157.55.2.182
157.55.7.138 - 157.55.7.182
157.55.10.202 - 157.55.10.246
157.55.11.138 - 157.55.11.182
157.55.11.200 - 157.55.11.244
157.55.13.10 - 157.55.13.116
157.55.13.138 - 157.55.13.182
157.55.16.9 - 157.55.16.99
157.55.16.140 - 157.55.16.231
157.55.17.73 - 157.55.17.117
157.55.17.137 - 157.55.17.228
157.55.18.9 - 157.55.18.53
157.55.18.74 - 157.55.18.119
157.55.18.138 - 157.55.18.183
157.55.18.202 - 157.55.18.251
157.55.19.10 - 157.55.19.55
157.55.19.74 - 157.55.19.119
157.55.19.138 - 157.55.19.183
157.55.19.202 - 157.55.19.251
157.55.20.10 - 157.55.20.55
157.55.20.74 - 157.55.20.183
157.55.20.202 - 157.55.20.247
157.55.21.10 - 157.55.21.55
157.55.21.74 - 157.55.21.119
157.55.21.138 - 157.55.21.183
157.55.21.202 - 157.55.21.252
157.55.22.10 - 157.55.22.55
157.55.22.74 - 157.55.22.119
157.55.22.138 - 157.55.22.183
157.55.22.202 - 157.55.22.247
157.55.23.10 - 157.55.23.55
157.55.23.74 - 157.55.23.183
157.55.36.139 - 157.55.36.228
157.55.37.10 - 157.55.37.103
157.55.37.139 - 157.55.37.228
157.55.38.10 - 157.55.38.99
157.55.38.139 - 157.55.38.236
157.55.39.10 - 157.55.39.99
157.55.39.139 - 157.55.39.228
157.55.48.7 - 157.55.48.51
157.55.48.71 - 157.55.48.115
157.55.48.135 - 157.55.48.243
157.55.50.7 - 157.55.50.51
157.55.50.71 - 157.55.50.115
157.55.98.8 - 157.55.98.52
157.55.98.74 - 157.55.98.118
157.55.99.10 - 157.55.99.54
157.55.99.199 - 157.55.99.243
157.55.100.10 - 157.55.100.54
157.55.102.7 - 157.55.102.51
157.55.103.135 - 157.55.103.179
157.55.103.199 - 157.55.103.243
157.55.106.10 - 157.55.106.13
157.55.106.74 - 157.55.106.118
157.55.106.138 - 157.55.106.182
157.55.106.202 - 157.55.106.246
157.55.107.10 - 157.55.107.102
157.55.107.138 - 157.55.107.182
157.55.107.202 - 157.55.107.246
157.55.108.10 - 157.55.108.118
157.55.108.138 - 157.55.108.182
157.55.108.202 - 157.55.108.246
157.55.109.10 - 157.55.109.118
157.55.109.138 - 157.55.109.182
157.55.109.202 - 157.55.109.246
157.55.110.10 - 157.55.110.115
157.55.110.135 - 157.55.110.179
157.55.110.202 - 157.55.110.246
157.55.111.74 - 157.55.111.118
157.55.111.138 - 157.55.111.139
157.55.111.202 - 157.55.111.246
157.55.112.199 - 157.55.112.243
157.55.114.10 - 157.55.114.54
157.55.114.202 - 157.55.114.241
157.55.116.8 - 157.55.116.97
157.55.118.74 - 157.55.118.113
157.55.118.138 - 157.55.118.177
157.55.154.135 - 157.55.154.224
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157.56.0.10 - 157.56.0.99
157.56.0.139 - 157.56.0.228
157.56.1.10 - 157.56.1.99
157.56.1.135 - 157.56.1.184
157.56.2.10 - 157.56.2.99
157.56.2.185 - 157.56.2.228
157.56.3.7 - 157.56.3.94
157.56.3.135 - 157.56.3.222
157.56.4.7 - 157.56.4.94
157.56.4.135 - 157.56.4.222
157.56.5.7 - 157.56.5.94
157.56.5.135 - 157.56.5.222
157.56.16.135 - 157.56.16.178
157.56.16.199 - 157.56.16.242
157.56.17.7 - 157.56.17.50
157.56.17.71 - 157.56.17.114
157.56.17.135 - 157.56.17.178
157.56.17.199 - 157.56.17.242
157.56.18.7 - 157.56.18.50
157.56.18.135 - 157.56.18.222
157.56.80.7 - 157.56.80.51
157.56.80.71 - 157.56.80.115
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