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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
26,993 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 156.70.56.0/22 | 1k | ARIN |  US | 19th Dec 1991 |
| 156.70.6.0/23 | 512 | ARIN | US | 19th Dec 1991 |
| 156.70.74.0/23 | 512 | ARIN | US | 19th Dec 1991 |
| 156.70.78.0/23 | 512 | ARIN | US | 19th Dec 1991 |
| 156.70.90.0/23 | 512 | ARIN | US | 19th Dec 1991 |
| 156.70.92.0/22 | 1k | ARIN | US | 19th Dec 1991 |
| 156.79.0.0/16 | 65.5k | ARIN | US | 19th Dec 1991 |
| 156.81.0.0/16 | 65.5k | ARIN | US | 19th Dec 1991 |
| 156.82.0.0/16 | 65.5k | ARIN | US | 19th Dec 1991 |
| 157.121.0.0/16 | 65.5k | ARIN | US | 19th Dec 1991 |
| 157.126.0.0/16 | 65.5k | ARIN | US | 2nd Jan 1992 |
| 157.14.192.0/20 | 4.1k | ARIN | US | 26th Jun 2024 |
| 157.14.224.0/20 | 4.1k | ARIN | US | 26th Jun 2024 |
| 157.14.240.0/21 | 2k | ARIN | US | 26th Jun 2024 |
| 157.146.0.0/16 | 65.5k | ARIN | US | 10th Jan 1992 |
| 157.170.0.0/16 | 65.5k | ARIN | US | 16th Jan 1992 |
| 157.183.0.0/16 | 65.5k | ARIN | US | 22nd Jan 1992 |
| 157.184.0.0/16 | 65.5k | ARIN | US | 22nd Jan 1992 |
| 157.189.0.0/16 | 65.5k | ARIN | US | 23rd Jan 1992 |
| 157.194.0.0/16 | 65.5k | ARIN | US | 24th Jan 1992 |
| 157.195.0.0/16 | 65.5k | ARIN | US | 24th Jan 1992 |
| 157.196.0.0/16 | 65.5k | ARIN | US | 24th Jan 1992 |
| 157.198.0.0/16 | 65.5k | ARIN | US | 28th Jan 1992 |
| 157.207.128.0/17 | 32.8k | ARIN | US | 28th Jan 1992 |
| 157.207.36.0/22 | 1k | ARIN | US | 28th Jan 1992 |
| 157.207.40.0/21 | 2k | ARIN | US | 28th Jan 1992 |
| 157.207.48.0/20 | 4.1k | ARIN | US | 28th Jan 1992 |
| 157.207.68.0/22 | 1k | ARIN | US | 28th Jan 1992 |
| 157.207.72.0/21 | 2k | ARIN | US | 28th Jan 1992 |
| 157.207.80.0/20 | 4.1k | ARIN | US | 28th Jan 1992 |
| 157.207.96.0/19 | 8.2k | ARIN | US | 28th Jan 1992 |
| 157.208.128.0/17 | 32.8k | ARIN | US | 8th Jan 1992 |
| 157.208.64.0/18 | 16.4k | ARIN | US | 8th Jan 1992 |
| 157.209.0.0/16 | 65.5k | ARIN | US | 29th Jan 1992 |
| 157.212.0.0/16 | 65.5k | ARIN | US | 15th Jun 2022 |
| 157.226.0.0/16 | 65.5k | ARIN | US | 30th Jan 1992 |
| 157.239.130.0/23 | 512 | ARIN | US | 4th Feb 1992 |
| 157.239.132.0/22 | 1k | ARIN | US | 4th Feb 1992 |
| 157.239.136.0/21 | 2k | ARIN | US | 4th Feb 1992 |
| 157.239.144.0/20 | 4.1k | ARIN | US | 4th Feb 1992 |
| 157.239.160.0/19 | 8.2k | ARIN | US | 4th Feb 1992 |
| 157.251.0.0/16 | 65.5k | ARIN | US | 7th Feb 1992 |
| 157.5.64.0/18 | 16.4k | ARIN | US | 12th Mar 2024 |
| 157.70.0.0/17 | 32.8k | RIPE NCC | US | 2nd Oct 1992 |
| 157.87.0.0/16 | 65.5k | ARIN | US | 16th Dec 1991 |
| 157.96.252.0/22 | 1k | ARIN | US | 30th Mar 2020 |
| 157.96.56.0/22 | 1k | ARIN | US | 30th Mar 2020 |
| 157.96.68.0/22 | 1k | ARIN | US | 30th Mar 2020 |
| 158.113.0.0/16 | 65.5k | ARIN | US | 26th Feb 1992 |
| 158.115.0.0/17 | 32.8k | ARIN | US | 26th Feb 1992 |