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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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.
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Countries with unannounced space registered through ARIN, largest first.
Unannounced blocks registered through ARIN
30,434 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 186.245.0.0/16 | 65.5k | ARIN |  US | 29th Jul 2026 |
| 187.126.128.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 187.13.32.0/20 | 4.1k | ARIN | US | 13th Mar 2025 |
| 187.41.128.0/17 | 32.8k | ARIN | US | 10th Apr 2026 |
| 187.42.192.0/18 | 16.4k | ARIN | US | 20th Feb 2025 |
| 187.52.224.0/19 | 8.2k | ARIN | US | 13th Mar 2025 |
| 187.52.32.0/20 | 4.1k | ARIN | US | 13th Mar 2025 |
| 187.53.160.0/19 | 8.2k | ARIN | US | 13th Mar 2025 |
| 187.54.0.0/20 | 4.1k | ARIN | US | 13th Mar 2025 |
| 187.54.224.0/19 | 8.2k | ARIN | US | 13th Mar 2025 |
| 187.55.128.0/19 | 8.2k | ARIN | US | 13th Mar 2025 |
| 187.55.160.0/20 | 4.1k | ARIN | US | 13th Mar 2025 |
| 187.55.64.0/19 | 8.2k | ARIN | US | 13th Mar 2025 |
| 187.7.192.0/20 | 4.1k | ARIN | US | 13th Mar 2025 |
| 187.7.32.0/19 | 8.2k | ARIN | US | 13th Mar 2025 |
| 187.78.0.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 187.78.128.0/19 | 8.2k | ARIN | US | 13th Mar 2025 |
| 187.78.192.0/18 | 16.4k | ARIN | US | 20th Feb 2025 |
| 187.79.0.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 187.79.128.0/20 | 4.1k | ARIN | US | 13th Mar 2025 |
| 188.209.144.0/21 | 2k | ARIN | US | 23rd Jul 2018 |
| 189.10.144.0/20 | 4.1k | ARIN | US | 13th Mar 2025 |
| 189.10.208.0/20 | 4.1k | ARIN | US | 13th Mar 2025 |
| 189.105.128.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 189.105.16.0/20 | 4.1k | ARIN | US | 13th Mar 2025 |
| 189.106.0.0/15 | 131k | ARIN | US | 29th Jul 2026 |
| 189.12.0.0/19 | 8.2k | ARIN | US | 13th Mar 2025 |
| 189.24.128.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 189.31.224.0/19 | 8.2k | ARIN | US | 13th Mar 2025 |
| 189.48.0.0/16 | 65.5k | ARIN | US | 29th Jul 2026 |
| 189.49.128.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 189.70.0.0/15 | 131k | ARIN | US | 29th Jul 2026 |
| 189.72.96.0/19 | 8.2k | ARIN | US | 13th Mar 2025 |
| 189.82.0.0/15 | 131k | ARIN | US | 29th Jul 2026 |
| 190.2.190.0/24 | 256 | ARIN | US | 26th May 2026 |
| 191.0.0.0/18 | 16.4k | ARIN | US | 24th Jul 2026 |
| 191.0.128.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 191.2.0.0/15 | 131k | ARIN | US | 29th Jul 2026 |
| 191.212.0.0/15 | 131k | ARIN | US | 29th Jul 2026 |
| 191.216.128.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 191.218.0.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 191.220.0.0/15 | 131k | ARIN | US | 29th Jul 2026 |
| 191.40.128.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 191.44.128.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 191.45.128.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 191.45.64.0/18 | 16.4k | ARIN | US | 24th Apr 2026 |
| 191.46.0.0/15 | 131k | ARIN | US | 29th Jul 2026 |
| 192.100.10.0/24 | 256 | ARIN | US | 12th Mar 1991 |
| 192.100.101.0/24 | 256 | ARIN |  CA | 19th Feb 1987 |
| 192.100.11.0/24 | 256 | ARIN | US | 12th Mar 1991 |