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CIDR Range

133.203.240.0/21

2.0K IPs /21 BIGLOBE Inc. AS2518 Japan APNIC
Addresses
2,048
2.0K
IP Range
133.203.240.0
→ 133.203.247.255
Sub-ranges
18+
within this block
PTR Density
100.0%
2.0K of 2.0K IPs have PTR

Reputation · trust score

A transparent 0–100 signal. Every entity starts at a neutral baseline of 65; threat-intel blocklists, exposure, reverse-DNS, routing and allocation each adjust it up or down. Higher is more trustworthy.

76/100
Moderate
How this score is built

Experimental · trust-vectors model v1.1.0 — a transparent heuristic, not a definitive verdict. How it works →

Ranges inside 133.203.240.0/21

CIDRIPsOrganizationASNCountry
133.203.240.0/22 1.0K BIGLOBE Inc. AS2518 JP
133.203.240.0/23 512 BIGLOBE Inc. AS2518 JP
133.203.246.0/23 512 BIGLOBE Inc. AS2518 JP
133.203.242.0/23 512 BIGLOBE Inc. AS2518 JP
133.203.244.0/24 256 BIGLOBE Inc. AS2518 JP
133.203.242.0/24 256 BIGLOBE Inc. AS2518 JP
133.203.244.128/25 128 BIGLOBE Inc. AS2518 JP
133.203.245.0/25 128 BIGLOBE Inc. AS2518 JP
133.203.243.128/25 128 BIGLOBE Inc. AS2518 JP
133.203.244.0/25 128 BIGLOBE Inc. AS2518 JP
133.203.245.128/25 128 BIGLOBE Inc. AS2518 JP
133.203.245.0/26 64 BIGLOBE Inc. AS2518 JP
133.203.244.192/26 64 BIGLOBE Inc. AS2518 JP
133.203.243.0/26 64 BIGLOBE Inc. AS2518 JP
133.203.243.64/26 64 BIGLOBE Inc. AS2518 JP
133.203.245.64/26 64 BIGLOBE Inc. AS2518 JP
133.203.244.160/27 32 BIGLOBE Inc. AS2518 JP
133.203.244.128/27 32 BIGLOBE Inc. AS2518 JP

Geolocation

First 256 of 2,048 IP addresses in 133.203.240.0/21

133.203.240.0 133.203.240.1 133.203.240.2 133.203.240.3 133.203.240.4 133.203.240.5 133.203.240.6 133.203.240.7 133.203.240.8 133.203.240.9 133.203.240.10 133.203.240.11 133.203.240.12 133.203.240.13 133.203.240.14 133.203.240.15 133.203.240.16 133.203.240.17 133.203.240.18 133.203.240.19 133.203.240.20 133.203.240.21 133.203.240.22 133.203.240.23 133.203.240.24 133.203.240.25 133.203.240.26 133.203.240.27 133.203.240.28 133.203.240.29 133.203.240.30 133.203.240.31 133.203.240.32 133.203.240.33 133.203.240.34 133.203.240.35 133.203.240.36 133.203.240.37 133.203.240.38 133.203.240.39 133.203.240.40 133.203.240.41 133.203.240.42 133.203.240.43 133.203.240.44 133.203.240.45 133.203.240.46 133.203.240.47 133.203.240.48 133.203.240.49 133.203.240.50 133.203.240.51 133.203.240.52 133.203.240.53 133.203.240.54 133.203.240.55 133.203.240.56 133.203.240.57 133.203.240.58 133.203.240.59 133.203.240.60 133.203.240.61 133.203.240.62 133.203.240.63 133.203.240.64 133.203.240.65 133.203.240.66 133.203.240.67 133.203.240.68 133.203.240.69 133.203.240.70 133.203.240.71 133.203.240.72 133.203.240.73 133.203.240.74 133.203.240.75 133.203.240.76 133.203.240.77 133.203.240.78 133.203.240.79 133.203.240.80 133.203.240.81 133.203.240.82 133.203.240.83 133.203.240.84 133.203.240.85 133.203.240.86 133.203.240.87 133.203.240.88 133.203.240.89 133.203.240.90 133.203.240.91 133.203.240.92 133.203.240.93 133.203.240.94 133.203.240.95 133.203.240.96 133.203.240.97 133.203.240.98 133.203.240.99 133.203.240.100 133.203.240.101 133.203.240.102 133.203.240.103 133.203.240.104 133.203.240.105 133.203.240.106 133.203.240.107 133.203.240.108 133.203.240.109 133.203.240.110 133.203.240.111 133.203.240.112 133.203.240.113 133.203.240.114 133.203.240.115 133.203.240.116 133.203.240.117 133.203.240.118 133.203.240.119 133.203.240.120 133.203.240.121 133.203.240.122 133.203.240.123 133.203.240.124 133.203.240.125 133.203.240.126 133.203.240.127 133.203.240.128 133.203.240.129 133.203.240.130 133.203.240.131 133.203.240.132 133.203.240.133 133.203.240.134 133.203.240.135 133.203.240.136 133.203.240.137 133.203.240.138 133.203.240.139 133.203.240.140 133.203.240.141 133.203.240.142 133.203.240.143 133.203.240.144 133.203.240.145 133.203.240.146 133.203.240.147 133.203.240.148 133.203.240.149 133.203.240.150 133.203.240.151 133.203.240.152 133.203.240.153 133.203.240.154 133.203.240.155 133.203.240.156 133.203.240.157 133.203.240.158 133.203.240.159 133.203.240.160 133.203.240.161 133.203.240.162 133.203.240.163 133.203.240.164 133.203.240.165 133.203.240.166 133.203.240.167 133.203.240.168 133.203.240.169 133.203.240.170 133.203.240.171 133.203.240.172 133.203.240.173 133.203.240.174 133.203.240.175 133.203.240.176 133.203.240.177 133.203.240.178 133.203.240.179 133.203.240.180 133.203.240.181 133.203.240.182 133.203.240.183 133.203.240.184 133.203.240.185 133.203.240.186 133.203.240.187 133.203.240.188 133.203.240.189 133.203.240.190 133.203.240.191 133.203.240.192 133.203.240.193 133.203.240.194 133.203.240.195 133.203.240.196 133.203.240.197 133.203.240.198 133.203.240.199 133.203.240.200 133.203.240.201 133.203.240.202 133.203.240.203 133.203.240.204 133.203.240.205 133.203.240.206 133.203.240.207 133.203.240.208 133.203.240.209 133.203.240.210 133.203.240.211 133.203.240.212 133.203.240.213 133.203.240.214 133.203.240.215 133.203.240.216 133.203.240.217 133.203.240.218 133.203.240.219 133.203.240.220 133.203.240.221 133.203.240.222 133.203.240.223 133.203.240.224 133.203.240.225 133.203.240.226 133.203.240.227 133.203.240.228 133.203.240.229 133.203.240.230 133.203.240.231 133.203.240.232 133.203.240.233 133.203.240.234 133.203.240.235 133.203.240.236 133.203.240.237 133.203.240.238 133.203.240.239 133.203.240.240 133.203.240.241 133.203.240.242 133.203.240.243 133.203.240.244 133.203.240.245 133.203.240.246 133.203.240.247 133.203.240.248 133.203.240.249 133.203.240.250 133.203.240.251 133.203.240.252 133.203.240.253 133.203.240.254 133.203.240.255 + 1.8K more (range too large to list inline)

BGP Routing

Live BGP anomalies →

Not announced as an exact prefix — covered by the announced supernet 133.200.0.0/14.

Announced prefix
133.200.0.0/14
Origin AS
AS2518
Announcement samples
5,071
Last seen
2026-07-23 08:11:19

Frequently Asked Questions

What is 133.203.240.0/21?

133.203.240.0/21 is a CIDR network block containing 2,048 IPv4 addresses (from 133.203.240.0 to 133.203.247.255). CIDR notation combines an IP address with a prefix length to define a range of addresses.

Who owns the 133.203.240.0/21 network?

The 133.203.240.0/21 range is allocated to BIGLOBE Inc. and announced via AS2518 from Japan.

Last updated: 2026-07-23 08:40:31 UTC
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