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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 unannounced space registered through ARIN, largest first.
Unannounced blocks registered through ARIN
30,441 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.133.122.0/24 | 256 | ARIN |  US | 9th Dec 1991 |
| 192.133.123.0/24 | 256 | ARIN | US | 9th Dec 1991 |
| 192.133.124.0/24 | 256 | ARIN | US | 9th Dec 1991 |
| 192.133.127.0/24 | 256 | ARIN | US | 9th Dec 1991 |
| 192.133.13.0/24 | 256 | ARIN | US | 11th Jun 2015 |
| 192.133.130.0/24 | 256 | ARIN | US | 9th Dec 1991 |
| 192.133.132.0/24 | 256 | ARIN | US | 9th Dec 1991 |
| 192.133.133.0/24 | 256 | ARIN | US | 9th Dec 1991 |
| 192.133.134.0/24 | 256 | ARIN | US | 9th Dec 1991 |
| 192.133.135.0/24 | 256 | ARIN | US | 9th Dec 1991 |
| 192.133.144.0/20 | 4.1k | ARIN | US | 10th Feb 1993 |
| 192.133.17.0/24 | 256 | ARIN | US | 31st Oct 1991 |
| 192.133.18.0/24 | 256 | ARIN | US | 31st Oct 1991 |
| 192.133.19.0/24 | 256 | ARIN | US | 31st Oct 1991 |
| 192.133.20.0/24 | 256 | ARIN | US | 31st Oct 1991 |
| 192.133.22.0/24 | 256 | ARIN | US | 31st Oct 1991 |
| 192.133.24.0/24 | 256 | ARIN | US | 31st Oct 1991 |
| 192.133.245.0/24 | 256 | ARIN | US | 10th Dec 1991 |
| 192.133.246.0/24 | 256 | ARIN | US | 10th Dec 1991 |
| 192.133.25.0/24 | 256 | ARIN | US | 1st Nov 1991 |
| 192.133.3.0/24 | 256 | ARIN | US | 27th Mar 1992 |
| 192.133.30.0/24 | 256 | ARIN | US | 15th Jan 1993 |
| 192.133.33.0/24 | 256 | ARIN | US | 5th Nov 1991 |
| 192.133.34.0/24 | 256 | ARIN | US | 6th Nov 1991 |
| 192.133.35.0/24 | 256 | ARIN | US | 6th Nov 1991 |
| 192.133.37.0/24 | 256 | ARIN | US | 6th Nov 1991 |
| 192.133.38.0/24 | 256 | ARIN | US | 6th Nov 1991 |
| 192.133.39.0/24 | 256 | ARIN | US | 6th Nov 1991 |
| 192.133.40.0/24 | 256 | ARIN | US | 6th Nov 1991 |
| 192.133.44.0/24 | 256 | ARIN | US | 6th Nov 1991 |
| 192.133.46.0/24 | 256 | ARIN | US | 6th Nov 1991 |
| 192.133.49.0/24 | 256 | ARIN |  CA | 2nd Apr 2026 |
| 192.133.50.0/24 | 256 | ARIN | US | 6th Nov 1991 |
| 192.133.51.0/24 | 256 | ARIN | US | 6th Nov 1991 |
| 192.133.52.0/24 | 256 | ARIN | US | 7th Nov 1991 |
| 192.133.56.0/24 | 256 | ARIN | US | 7th Nov 1991 |
| 192.133.57.0/24 | 256 | ARIN | US | 7th Nov 1991 |
| 192.133.59.0/24 | 256 | ARIN | US | 7th Nov 1991 |
| 192.133.61.0/24 | 256 | ARIN | US | 7th Nov 1991 |
| 192.133.62.0/24 | 256 | ARIN | US | 8th Nov 1991 |
| 192.133.65.0/24 | 256 | ARIN | US | 13th Nov 1991 |
| 192.133.68.0/24 | 256 | ARIN | US | 14th Nov 1991 |
| 192.133.69.0/24 | 256 | ARIN | US | 14th Nov 1991 |
| 192.133.70.0/24 | 256 | ARIN | US | 14th Nov 1991 |
| 192.133.73.0/24 | 256 | ARIN | US | 18th Nov 1991 |
| 192.133.74.0/24 | 256 | ARIN | US | 18th Nov 1991 |
| 192.133.8.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.133.88.0/24 | 256 | ARIN | US | 25th Nov 1991 |
| 192.133.89.0/24 | 256 | ARIN | US | 25th Nov 1991 |
| 192.133.9.0/24 | 256 | ARIN | US | 30th Oct 1991 |