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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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.
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Countries with the most unannounced blocks, largest first.
Unannounced blocks in United States
26,951 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 206.83.44.0/24 | 256 | ARIN |  US | 21st Aug 2019 |
| 206.88.0.0/13 | 524k | ARIN | US | 9th Aug 1995 |
| 206.96.64.0/19 | 8.2k | ARIN | US | 15th Aug 1995 |
| 206.97.128.0/17 | 32.8k | ARIN | US | 15th Aug 1995 |
| 206.97.24.0/21 | 2k | ARIN | US | 15th Aug 1995 |
| 206.98.0.0/16 | 65.5k | ARIN | US | 15th Aug 1995 |
| 206.99.120.0/21 | 2k | ARIN | US | 15th Aug 1995 |
| 207.100.0.0/16 | 65.5k | ARIN | US | 28th Mar 1996 |
| 207.11.192.0/19 | 8.2k | ARIN | US | 26th Mar 2025 |
| 207.110.64.0/18 | 16.4k | ARIN | US | 24th Apr 1996 |
| 207.111.0.0/18 | 16.4k | ARIN | US | 9th May 1996 |
| 207.115.0.0/18 | 16.4k | ARIN | US | 19th Jun 1996 |
| 207.115.128.0/17 | 32.8k | ARIN | US | 19th Jun 1996 |
| 207.124.0.0/16 | 65.5k | ARIN | US | 1st May 1996 |
| 207.126.224.0/20 | 4.1k | ARIN | US | 5th Mar 2002 |
| 207.126.32.0/21 | 2k | ARIN | US | 8th Apr 1998 |
| 207.146.0.0/15 | 131k | ARIN | US | 6th Jun 1996 |
| 207.149.0.0/16 | 65.5k | ARIN | US | 11th Jun 1996 |
| 207.152.192.0/18 | 16.4k | ARIN | US | 19th Jun 1996 |
| 207.159.192.0/18 | 16.4k | ARIN | US | 2nd Jul 1996 |
| 207.162.224.0/20 | 4.1k | ARIN | US | 25th Feb 1999 |
| 207.166.138.0/24 | 256 | ARIN | US | 24th Jul 1996 |
| 207.166.144.0/24 | 256 | ARIN | US | 3rd Mar 2025 |
| 207.166.146.0/23 | 512 | ARIN | US | 12th Mar 2025 |
| 207.166.27.0/24 | 256 | ARIN | US | 3rd Jul 1996 |
| 207.166.44.0/22 | 1k | ARIN | US | 1st Dec 2016 |
| 207.166.48.0/24 | 256 | ARIN | US | 1st Dec 2016 |
| 207.167.112.0/22 | 1k | ARIN | US | 7th Jan 2022 |
| 207.167.121.0/24 | 256 | ARIN | US | 7th Jan 2022 |
| 207.167.123.0/24 | 256 | ARIN | US | 12th Jan 2022 |
| 207.167.160.0/19 | 8.2k | ARIN | US | 12th Aug 1999 |
| 207.169.0.0/16 | 65.5k | ARIN | US | 9th Nov 2023 |
| 207.170.64.0/18 | 16.4k | ARIN | US | 2nd Aug 1996 |
| 207.174.112.0/24 | 256 | ARIN | US | 1st Jul 2026 |
| 207.174.116.0/24 | 256 | ARIN | US | 3rd Apr 2023 |
| 207.174.168.0/22 | 1k | ARIN | US | 4th Jan 2022 |
| 207.174.173.0/24 | 256 | ARIN | US | 6th Oct 1998 |
| 207.174.203.0/24 | 256 | ARIN | US | 1st Jul 2025 |
| 207.174.208.0/23 | 512 | ARIN | US | 3rd Oct 2025 |
| 207.174.210.0/23 | 512 | ARIN | US | 9th Jun 1999 |
| 207.174.52.0/22 | 1k | ARIN | US | 4th Apr 2023 |
| 207.174.58.0/24 | 256 | ARIN | US | 4th Apr 2023 |
| 207.174.63.0/24 | 256 | ARIN | US | 4th Apr 2023 |
| 207.174.88.0/23 | 512 | ARIN | US | 4th Apr 2023 |
| 207.174.91.0/24 | 256 | ARIN | US | 7th Apr 2023 |
| 207.174.94.0/24 | 256 | ARIN | US | 4th Apr 2023 |
| 207.174.96.0/24 | 256 | ARIN | US | 4th Apr 2023 |
| 207.174.99.0/24 | 256 | ARIN | US | 3rd Apr 2023 |
| 207.183.112.0/20 | 4.1k | ARIN | US | 8th Mar 2001 |
| 207.183.192.0/19 | 8.2k | ARIN | US | 18th Oct 1996 |