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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,201 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.35.53.0/24 | 256 | ARIN |  US | 18th Jul 1988 |
| 192.35.54.0/24 | 256 | ARIN | US | 18th Jul 1988 |
| 192.35.55.0/24 | 256 | ARIN | US | 18th Jul 1988 |
| 192.35.56.0/24 | 256 | ARIN | US | 18th Jul 1988 |
| 192.35.57.0/24 | 256 | ARIN | US | 18th Jul 1988 |
| 192.35.60.0/24 | 256 | ARIN | US | 19th Jul 1988 |
| 192.35.65.0/24 | 256 | RIPE NCC |  DE | 2nd Mar 1988 |
| 192.35.73.0/24 | 256 | ARIN | US | 2nd Mar 1988 |
| 192.35.77.0/24 | 256 | ARIN | US | 30th Mar 1988 |
| 192.35.78.0/24 | 256 | ARIN | US | 30th Mar 1988 |
| 192.35.80.0/24 | 256 | ARIN | US | 7th Mar 1988 |
| 192.35.87.0/24 | 256 | ARIN | US | 15th Mar 1988 |
| 192.35.90.0/24 | 256 | RIPE NCC | DE | 5th Jan 1989 |
| 192.35.91.0/24 | 256 | ARIN | US | 18th Mar 1988 |
| 192.35.95.0/24 | 256 | ARIN | US | 18th Mar 1988 |
| 192.35.96.0/24 | 256 | ARIN | US | 25th Mar 1988 |
| 192.35.97.0/24 | 256 | ARIN | US | 25th Mar 1988 |
| 192.37.0.0/16 | 65.5k | RIPE NCC |  CH | 20th Aug 1993 |
| 192.4.240.0/23 | 512 | ARIN | US | 30th Jan 1993 |
| 192.40.0.0/22 | 1k | APNIC |  KR | 29th Nov 2012 |
| 192.40.116.0/24 | 256 | ARIN | US | 23rd May 1988 |
| 192.40.118.0/23 | 512 | ARIN | US | 9th Sept 2014 |
| 192.40.144.0/21 | 2k | ARIN | US | 4th Dec 2012 |
| 192.40.152.0/23 | 512 | ARIN | US | 16th Sept 2014 |
| 192.40.155.0/24 | 256 | ARIN | US | 23rd May 1988 |
| 192.40.156.0/24 | 256 | ARIN | US | 2nd Mar 2004 |
| 192.40.159.0/24 | 256 | ARIN | US | 2nd Jul 1992 |
| 192.40.201.0/24 | 256 | ARIN | US | 28th Jan 1993 |
| 192.40.202.0/23 | 512 | ARIN | US | 26th Sept 2014 |
| 192.40.217.0/24 | 256 | ARIN |  CA | 7th Jul 1992 |
| 192.40.228.0/24 | 256 | RIPE NCC |  FI | 30th Aug 2001 |
| 192.40.245.0/24 | 256 | ARIN | US | 2nd Mar 2004 |
| 192.40.248.0/24 | 256 | ARIN | US | 2nd Mar 2004 |
| 192.40.249.0/24 | 256 | ARIN | US | 23rd May 1988 |
| 192.40.25.0/24 | 256 | ARIN | US | 2nd Mar 2004 |
| 192.40.250.0/23 | 512 | ARIN | US | 7th Oct 2014 |
| 192.40.254.0/24 | 256 | ARIN | CA | 7th Jan 1994 |
| 192.40.255.0/24 | 256 | ARIN | US | 25th Sept 2025 |
| 192.40.29.0/24 | 256 | ARIN | US | 11th Apr 1994 |
| 192.40.47.0/24 | 256 | ARIN | US | 23rd May 1988 |
| 192.40.48.0/24 | 256 | ARIN | US | 23rd May 1988 |
| 192.40.50.0/24 | 256 | ARIN | US | 29th Sept 2023 |
| 192.40.53.0/24 | 256 | ARIN | US | 23rd May 1988 |
| 192.40.54.0/24 | 256 | ARIN | US | 23rd May 1988 |
| 192.40.61.0/24 | 256 | ARIN | US | 2nd Mar 2004 |
| 192.40.62.0/23 | 512 | ARIN | US | 3rd Sept 2014 |
| 192.40.64.0/24 | 256 | ARIN | US | 25th Jun 2014 |
| 192.40.65.0/24 | 256 | ARIN | US | 13th Aug 1993 |
| 192.41.137.0/24 | 256 | ARIN | US | 8th Jun 1988 |
| 192.41.138.0/23 | 512 | ARIN | US | 17th Sept 2014 |