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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 192.133.134.0/24 | 256 | ARIN |  US | 9th Dec 1991 |
| 192.133.135.0/24 | 256 | ARIN | US | 9th Dec 1991 |
| 192.133.14.0/24 | 256 | APNIC |  ID | 14th Aug 2026 |
| 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 |
| 192.133.250.0/24 | 256 | AFRINIC |  ZA | 16th Dec 1991 |
| 192.133.3.0/24 | 256 | ARIN | US | 27th Mar 1992 |
| 192.133.30.0/24 | 256 | ARIN | US | 15th Jan 1993 |
| 192.133.32.0/24 | 256 | RIPE NCC |  NO | 5th Nov 1991 |
| 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 |
| 192.133.36.0/24 | 256 | RIPE NCC |  IL | 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 |
| 192.133.53.0/24 | 256 | RIPE NCC |  NL | 7th Nov 1991 |
| 192.133.54.0/24 | 256 | RIPE NCC |  PT | 7th Nov 1991 |
| 192.133.55.0/24 | 256 | RIPE NCC | PT | 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 |
| 192.133.58.0/24 | 256 | RIPE NCC |  GB | 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 |
| 192.133.64.0/24 | 256 | RIPE NCC | NO | 13th Nov 1991 |
| 192.133.65.0/24 | 256 | ARIN | US | 13th Nov 1991 |
| 192.133.66.0/24 | 256 | APNIC |  PH | 16th Aug 2026 |
| 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 |