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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,124 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.131.239.0/24 | 256 | ARIN |  US | 30th Oct 1991 |
| 192.131.24.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.131.240.0/24 | 256 | ARIN | US | 13th May 1992 |
| 192.131.241.0/24 | 256 | ARIN | US | 29th Mar 1992 |
| 192.131.242.0/24 | 256 | ARIN | US | 29th Mar 1992 |
| 192.131.243.0/24 | 256 | ARIN | US | 31st Oct 1991 |
| 192.131.244.0/24 | 256 | ARIN | US | 31st Oct 1991 |
| 192.131.245.0/24 | 256 | ARIN | US | 31st Oct 1991 |
| 192.131.246.0/24 | 256 | ARIN | US | 31st Oct 1991 |
| 192.131.248.0/24 | 256 | ARIN | US | 14th Feb 1992 |
| 192.131.250.0/24 | 256 | ARIN | US | 31st Oct 1991 |
| 192.131.253.0/24 | 256 | ARIN | US | 31st Oct 1991 |
| 192.131.26.0/24 | 256 | RIPE NCC |  SE | 30th Oct 1991 |
| 192.131.27.0/24 | 256 | APNIC |  AU | 9th Jan 2001 |
| 192.131.28.0/23 | 512 | APNIC | AU | 9th Jan 2001 |
| 192.131.3.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.131.30.0/24 | 256 | APNIC | AU | 9th Jan 2001 |
| 192.131.31.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.131.4.0/23 | 512 | ARIN | US | 4th Feb 2015 |
| 192.131.45.0/24 | 256 | ARIN | US | 13th May 1992 |
| 192.131.46.0/23 | 512 | ARIN | US | 13th May 1992 |
| 192.131.6.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.131.7.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.131.77.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.131.78.0/24 | 256 | ARIN | US | 29th Oct 1991 |
| 192.131.79.0/24 | 256 | RIPE NCC |  GB | 29th Oct 1991 |
| 192.131.8.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.131.82.0/24 | 256 | ARIN | US | 28th Apr 1992 |
| 192.131.83.0/24 | 256 | ARIN | US | 28th Apr 1992 |
| 192.131.84.0/24 | 256 | ARIN | US | 28th Apr 1992 |
| 192.131.85.0/24 | 256 | ARIN | US | 28th Apr 1992 |
| 192.131.86.0/24 | 256 | ARIN | US | 28th Apr 1992 |
| 192.131.87.0/24 | 256 | ARIN | US | 28th Apr 1992 |
| 192.131.89.0/24 | 256 | RIPE NCC | GB | 30th Oct 1991 |
| 192.131.9.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.131.94.0/24 | 256 | ARIN |  CA | 30th Oct 1991 |
| 192.131.95.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.131.96.0/24 | 256 | RIPE NCC |  FI | 30th Oct 1991 |
| 192.131.98.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.132.10.0/24 | 256 | RIPE NCC |  IT | 5th Nov 1991 |
| 192.132.100.0/24 | 256 | ARIN | US | 14th Nov 1991 |
| 192.132.101.0/24 | 256 | ARIN | US | 14th Nov 1991 |
| 192.132.103.0/24 | 256 | ARIN | US | 14th Nov 1991 |
| 192.132.105.0/24 | 256 | ARIN | US | 4th May 1992 |
| 192.132.11.0/24 | 256 | RIPE NCC |  NO | 5th Nov 1991 |
| 192.132.12.0/24 | 256 | ARIN | US | 5th Nov 1991 |
| 192.132.13.0/24 | 256 | ARIN | US | 5th Nov 1991 |
| 192.132.14.0/24 | 256 | ARIN | US | 5th Nov 1991 |
| 192.132.16.0/24 | 256 | ARIN | US | 7th Nov 1991 |
| 192.132.17.0/24 | 256 | ARIN | US | 7th Nov 1991 |