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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,108 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 191.216.48.0/20 | 4.1k | RIPE NCC |  LT | 13th Mar 2025 |
| 191.216.80.0/20 | 4.1k | RIPE NCC | LT | 13th Mar 2025 |
| 191.217.160.0/20 | 4.1k | RIPE NCC |  US | 13th Mar 2025 |
| 191.217.192.0/18 | 16.4k | RIPE NCC | US | 6th Mar 2025 |
| 191.218.0.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 191.219.128.0/19 | 8.2k | RIPE NCC |  SG | 13th Mar 2025 |
| 191.219.192.0/18 | 16.4k | LACNIC |  BR | 11th Dec 2013 |
| 191.220.0.0/15 | 131k | ARIN | US | 29th Jul 2026 |
| 191.223.48.0/20 | 4.1k | LACNIC | BR | 11th Dec 2013 |
| 191.227.134.0/23 | 512 | LACNIC | BR | 4th Sept 2013 |
| 191.227.140.0/23 | 512 | LACNIC | BR | 4th Sept 2013 |
| 191.242.32.0/22 | 1k | LACNIC | BR | 17th Dec 2013 |
| 191.243.80.0/21 | 2k | LACNIC | BR | 23rd Dec 2013 |
| 191.253.128.0/18 | 16.4k | LACNIC | BR | 15th Jan 2014 |
| 191.253.80.0/20 | 4.1k | LACNIC | BR | 14th Jan 2014 |
| 191.36.238.0/24 | 256 | LACNIC | BR | 19th Mar 2014 |
| 191.40.128.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 191.43.0.0/16 | 65.5k | APNIC | SG | 20th Feb 2025 |
| 191.44.128.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 191.45.0.0/19 | 8.2k | RIPE NCC | LT | 6th Mar 2025 |
| 191.45.128.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 191.45.32.0/20 | 4.1k | RIPE NCC |  AE | 13th Mar 2025 |
| 191.45.64.0/18 | 16.4k | ARIN | US | 24th Apr 2026 |
| 191.46.0.0/15 | 131k | ARIN | US | 29th Jul 2026 |
| 191.52.220.0/22 | 1k | LACNIC |  MX | 11th Jun 2020 |
| 191.7.128.0/21 | 2k | LACNIC | BR | 28th Feb 2014 |
| 191.7.35.0/24 | 256 | LACNIC | BR | 19th Feb 2014 |
| 192.100.1.0/24 | 256 | AFRINIC |  ZA | 8th Mar 1991 |
| 192.100.10.0/24 | 256 | ARIN | US | 12th Mar 1991 |
| 192.100.101.0/24 | 256 | ARIN |  CA | 19th Feb 1987 |
| 192.100.102.0/23 | 512 | RIPE NCC |  GB | 12th Apr 1991 |
| 192.100.11.0/24 | 256 | ARIN | US | 12th Mar 1991 |
| 192.100.12.0/24 | 256 | ARIN | US | 12th Mar 1991 |
| 192.100.13.0/24 | 256 | ARIN | US | 12th Mar 1991 |
| 192.100.132.0/23 | 512 | RIPE NCC | GB | 12th Apr 1991 |
| 192.100.136.0/22 | 1k | RIPE NCC | GB | 12th Apr 1991 |
| 192.100.140.0/24 | 256 | RIPE NCC | GB | 12th Apr 1991 |
| 192.100.141.0/24 | 256 | ARIN | US | 15th Apr 1991 |
| 192.100.142.0/24 | 256 | ARIN | US | 15th Apr 1991 |
| 192.100.144.0/24 | 256 | RIPE NCC | GB | 16th Apr 1991 |
| 192.100.145.0/24 | 256 | ARIN | US | 17th Apr 1991 |
| 192.100.146.0/24 | 256 | ARIN | US | 17th Apr 1991 |
| 192.100.147.0/24 | 256 | ARIN | US | 22nd Apr 1991 |
| 192.100.15.0/24 | 256 | ARIN | US | 12th Mar 1991 |
| 192.100.154.0/24 | 256 | RIPE NCC | GB | 22nd Apr 1991 |
| 192.100.155.0/24 | 256 | LACNIC | MX | 22nd Apr 1991 |
| 192.100.156.0/24 | 256 | LACNIC | MX | 22nd Apr 1991 |
| 192.100.158.0/24 | 256 | LACNIC | MX | 19th Mar 1992 |
| 192.100.160.0/24 | 256 | LACNIC | MX | 21st Dec 1992 |
| 192.100.167.0/24 | 256 | LACNIC | MX | 21st Dec 1992 |