Allocated but unannounced space
Every block here was allocated or assigned by a regional internet registry, and none of them appeared in any routing table we collected at our last snapshot — neither as a route of their own, nor covered by a larger announcement, nor carved up into more specifics.
“Unannounced” does not mean “unused”
Plenty of allocated space is deliberately kept off the public internet: private interconnects, lab and lawful-intercept ranges, networks reachable only inside one operator, and space held in reserve. Some of it is announced somewhere our collectors cannot see, which is a limit of our vantage points rather than a fact about the block.
It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today. Nothing on this page means a block is unallocated, available, or free to announce.
Browse by registry
Browse by country
Countries with the most unannounced blocks, largest first.
Unannounced blocks
84,584 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 37.148.166.0/23 | 512 | RIPE NCC |  NL | 6th Mar 2012 |
| 37.153.137.0/24 | 256 | RIPE NCC |  TR | 13th Mar 2012 |
| 37.153.174.0/23 | 512 | RIPE NCC |  RS | 13th Mar 2012 |
| 37.156.0.0/22 | 1k | RIPE NCC |  IR | 13th Mar 2012 |
| 37.156.175.0/24 | 256 | RIPE NCC |  GE | 13th Mar 2012 |
| 37.156.32.0/23 | 512 | RIPE NCC |  PL | 13th Mar 2012 |
| 37.156.7.0/24 | 256 | RIPE NCC |  RO | 13th Mar 2012 |
| 37.18.176.0/21 | 2k | RIPE NCC |  US | 20th Dec 2011 |
| 37.18.84.0/24 | 256 | RIPE NCC |  RU | 20th Dec 2011 |
| 37.186.28.0/23 | 512 | RIPE NCC |  SA | 20th Mar 2012 |
| 37.186.30.0/24 | 256 | RIPE NCC | SA | 20th Mar 2012 |
| 37.186.31.0/24 | 256 | RIPE NCC | SA | 20th Mar 2012 |
| 37.19.24.0/21 | 2k | RIPE NCC |  BA | 21st Dec 2011 |
| 37.200.84.0/24 | 256 | RIPE NCC |  DE | 4th May 2020 |
| 37.202.32.0/20 | 4.1k | RIPE NCC | PL | 23rd Mar 2012 |
| 37.209.240.0/21 | 2k | RIPE NCC | RU | 2nd Apr 2012 |
| 37.220.152.0/21 | 2k | RIPE NCC | RU | 5th Apr 2012 |
| 37.220.48.0/20 | 4.1k | RIPE NCC |  FR | 3rd Apr 2012 |
| 37.220.64.0/20 | 4.1k | RIPE NCC | RS | 3rd Apr 2012 |
| 37.221.124.0/22 | 1k | RIPE NCC |  MD | 12th Nov 2018 |
| 37.228.131.0/24 | 256 | RIPE NCC | IR | 10th Apr 2012 |
| 37.228.133.0/24 | 256 | RIPE NCC | IR | 10th Apr 2012 |
| 37.228.135.0/24 | 256 | RIPE NCC | IR | 10th Apr 2012 |
| 37.228.72.0/21 | 2k | RIPE NCC |  BE | 10th Apr 2012 |
| 37.230.188.0/22 | 1k | RIPE NCC | RU | 11th Apr 2012 |
| 37.233.81.0/24 | 256 | RIPE NCC | RU | 13th Apr 2012 |
| 37.233.82.0/23 | 512 | RIPE NCC | RU | 13th Apr 2012 |
| 37.233.84.0/23 | 512 | RIPE NCC | RU | 13th Apr 2012 |
| 37.233.86.0/24 | 256 | RIPE NCC | RU | 13th Apr 2012 |
| 37.235.64.0/21 | 2k | RIPE NCC | RU | 16th Apr 2012 |
| 37.25.40.0/22 | 1k | RIPE NCC | FR | 23rd Dec 2011 |
| 37.252.176.0/21 | 2k | RIPE NCC | NL | 20th Apr 2012 |
| 37.252.216.0/22 | 1k | RIPE NCC |  AM | 14th Jun 2018 |
| 37.252.223.0/24 | 256 | RIPE NCC | DE | 27th May 2021 |
| 37.26.112.0/20 | 4.1k | RIPE NCC | NL | 27th Dec 2011 |
| 37.26.160.0/21 | 2k | RIPE NCC | PL | 28th Dec 2011 |
| 37.32.104.0/21 | 2k | RIPE NCC |  IT | 2nd Apr 2012 |
| 37.34.32.0/21 | 2k | RIPE NCC | IT | 3rd Jan 2012 |
| 37.35.72.0/21 | 2k | RIPE NCC | DE | 5th Jan 2012 |
| 37.44.128.0/19 | 8.2k | RIPE NCC |  NO | 9th Jan 2012 |
| 37.44.220.0/22 | 1k | RIPE NCC |  AT | 12th Nov 2018 |
| 37.44.240.0/22 | 1k | RIPE NCC | BE | 12th Nov 2018 |
| 37.46.216.0/21 | 2k | RIPE NCC |  UA | 16th Jan 2012 |
| 37.58.64.0/18 | 16.4k | RIPE NCC | NL | 16th Jan 2012 |
| 37.60.160.0/21 | 2k | RIPE NCC |  DK | 18th Jan 2012 |
| 37.72.102.0/24 | 256 | RIPE NCC | NL | 26th Jan 2012 |
| 37.72.131.0/24 | 256 | RIPE NCC |  HK | 20th Sept 2021 |
| 37.72.139.0/24 | 256 | RIPE NCC |  SC | 21st Sept 2021 |
| 37.75.152.0/21 | 2k | RIPE NCC | NL | 31st Jan 2012 |
| 37.75.232.0/21 | 2k | RIPE NCC |  GB | 31st Jan 2012 |