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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 in United States
27,001 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.129.96.0/24 | 256 | ARIN |  US | 24th Sept 1991 |
| 192.131.10.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.131.100.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.131.103.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.131.104.0/24 | 256 | ARIN | US | 12th Dec 1991 |
| 192.131.105.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.131.106.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.131.11.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.131.111.0/24 | 256 | ARIN | US | 23rd Jan 1992 |
| 192.131.112.0/21 | 2k | ARIN | US | 23rd Jan 1992 |
| 192.131.12.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.131.120.0/24 | 256 | ARIN | US | 23rd Jan 1992 |
| 192.131.121.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.131.122.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.131.126.0/24 | 256 | ARIN | US | 28th Oct 1991 |
| 192.131.127.0/24 | 256 | ARIN | US | 28th Oct 1991 |
| 192.131.128.0/24 | 256 | ARIN | US | 22nd Jan 1996 |
| 192.131.130.0/24 | 256 | ARIN | US | 28th Oct 1991 |
| 192.131.131.0/24 | 256 | ARIN | US | 28th Oct 1991 |
| 192.131.135.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.131.14.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.131.143.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.131.144.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.131.146.0/24 | 256 | ARIN | US | 28th Apr 1992 |
| 192.131.148.0/24 | 256 | ARIN | US | 26th Nov 1991 |
| 192.131.151.0/24 | 256 | ARIN | US | 26th Nov 1991 |
| 192.131.156.0/22 | 1k | ARIN | US | 28th Apr 1992 |
| 192.131.160.0/20 | 4.1k | ARIN | US | 28th Apr 1992 |
| 192.131.176.0/22 | 1k | ARIN | US | 28th Apr 1992 |
| 192.131.180.0/23 | 512 | ARIN | US | 28th Apr 1992 |
| 192.131.186.0/23 | 512 | ARIN | US | 28th Apr 1992 |
| 192.131.2.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.131.224.0/24 | 256 | ARIN | US | 28th Apr 1992 |
| 192.131.225.0/24 | 256 | ARIN | US | 28th Apr 1992 |
| 192.131.226.0/23 | 512 | ARIN | US | 28th Apr 1992 |
| 192.131.228.0/22 | 1k | ARIN | US | 28th Apr 1992 |
| 192.131.23.0/24 | 256 | ARIN | US | 30th Oct 1991 |
| 192.131.235.0/24 | 256 | ARIN | US | 29th Mar 1992 |
| 192.131.236.0/24 | 256 | ARIN | US | 29th Mar 1992 |
| 192.131.237.0/24 | 256 | ARIN | US | 29th Mar 1992 |
| 192.131.238.0/24 | 256 | ARIN | US | 29th Mar 1992 |
| 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 |