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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
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Countries with the most unannounced blocks, largest first.
Unannounced blocks
85,285 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 199.244.244.0/24 | 256 | ARIN |  US | 12th Sept 1994 |
| 199.244.247.0/24 | 256 | ARIN | US | 12th Sept 1994 |
| 199.244.248.0/24 | 256 | ARIN | US | 13th Sept 1994 |
| 199.244.249.0/24 | 256 | ARIN | US | 23rd Apr 2012 |
| 199.244.250.0/23 | 512 | ARIN | US | 8th Jul 2015 |
| 199.244.56.0/21 | 2k | ARIN | US | 18th Mar 2026 |
| 199.244.64.0/22 | 1k | ARIN | US | 7th Aug 2012 |
| 199.244.68.0/22 | 1k | ARIN | US | 8th Aug 2012 |
| 199.245.0.0/20 | 4.1k | ARIN | US | 2nd May 1994 |
| 199.245.102.0/24 | 256 | ARIN | US | 19th Jul 1994 |
| 199.245.104.0/24 | 256 | ARIN | US | 19th Jul 1994 |
| 199.245.106.0/23 | 512 | ARIN | US | 19th Jun 1997 |
| 199.245.108.0/23 | 512 | ARIN | US | 19th Jun 1997 |
| 199.245.110.0/24 | 256 | ARIN | US | 19th Jul 1994 |
| 199.245.111.0/24 | 256 | ARIN | US | 20th Jul 1994 |
| 199.245.112.0/23 | 512 | ARIN | US | 19th Jan 2023 |
| 199.245.114.0/23 | 512 | ARIN | US | 20th Jul 1994 |
| 199.245.116.0/24 | 256 | ARIN | US | 25th Apr 2012 |
| 199.245.117.0/24 | 256 | ARIN | US | 5th May 1994 |
| 199.245.118.0/23 | 512 | ARIN | US | 5th May 1994 |
| 199.245.120.0/23 | 512 | ARIN | US | 5th May 1994 |
| 199.245.122.0/24 | 256 | ARIN | US | 5th May 1994 |
| 199.245.124.0/24 | 256 | ARIN | US | 5th May 1994 |
| 199.245.125.0/24 | 256 | ARIN | US | 5th May 1994 |
| 199.245.127.0/24 | 256 | ARIN | US | 5th May 1994 |
| 199.245.128.0/23 | 512 | ARIN | US | 5th May 1994 |
| 199.245.130.0/24 | 256 | ARIN | US | 5th May 1994 |
| 199.245.131.0/24 | 256 | ARIN | US | 5th May 1994 |
| 199.245.132.0/24 | 256 | ARIN | US | 5th May 1994 |
| 199.245.133.0/24 | 256 | ARIN | US | 5th May 1994 |
| 199.245.134.0/24 | 256 | ARIN | US | 5th May 1994 |
| 199.245.135.0/24 | 256 | ARIN | US | 5th May 1994 |
| 199.245.136.0/24 | 256 | ARIN | US | 5th May 1994 |
| 199.245.137.0/24 | 256 | ARIN | US | 5th May 1994 |
| 199.245.138.0/24 | 256 | ARIN | US | 5th May 1994 |
| 199.245.139.0/24 | 256 | ARIN | US | 5th May 1994 |
| 199.245.141.0/24 | 256 | ARIN | US | 30th Mar 2012 |
| 199.245.145.0/24 | 256 | ARIN | US | 18th May 1994 |
| 199.245.146.0/24 | 256 | ARIN | US | 1st Jul 2026 |
| 199.245.147.0/24 | 256 | ARIN | US | 2nd Jul 2026 |
| 199.245.148.0/24 | 256 | ARIN |  CA | 2nd Jul 2026 |
| 199.245.150.0/24 | 256 | ARIN | US | 2nd Jul 2026 |
| 199.245.151.0/24 | 256 | ARIN | US | 21st Jul 2026 |
| 199.245.152.0/24 | 256 | ARIN | US | 2nd Jul 2026 |
| 199.245.153.0/24 | 256 | ARIN | US | 18th May 1994 |
| 199.245.154.0/24 | 256 | ARIN | US | 18th May 1994 |
| 199.245.157.0/24 | 256 | ARIN | US | 18th May 1994 |
| 199.245.158.0/24 | 256 | ARIN | US | 18th May 1994 |
| 199.245.159.0/24 | 256 | ARIN | US | 18th May 1994 |
| 199.245.160.0/23 | 512 | ARIN | US | 18th May 1994 |