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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,285 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 199.181.8.0/21 | 2k | ARIN |  US | 7th Mar 1994 |
| 199.181.80.0/24 | 256 | ARIN | US | 21st Jul 1994 |
| 199.181.83.0/24 | 256 | ARIN | US | 25th Jul 1994 |
| 199.181.84.0/24 | 256 | ARIN | US | 25th Jul 1994 |
| 199.181.85.0/24 | 256 | ARIN | US | 25th Jul 1994 |
| 199.181.86.0/24 | 256 | ARIN | US | 25th Jul 1994 |
| 199.181.87.0/24 | 256 | ARIN | US | 25th Jul 1994 |
| 199.181.97.0/24 | 256 | ARIN | US | 25th Jul 1994 |
| 199.181.98.0/24 | 256 | ARIN | US | 25th Jul 1994 |
| 199.181.99.0/24 | 256 | ARIN | US | 25th Jul 1994 |
| 199.182.120.0/22 | 1k | ARIN | US | 17th Apr 2012 |
| 199.182.176.0/21 | 2k | ARIN |  CA | 23rd Apr 2012 |
| 199.182.200.0/22 | 1k | ARIN | US | 25th Apr 2012 |
| 199.182.216.0/22 | 1k | ARIN | CA | 25th Apr 2012 |
| 199.182.48.0/22 | 1k | ARIN | US | 11th Apr 2012 |
| 199.184.0.0/21 | 2k | ARIN | US | 8th Mar 1994 |
| 199.184.102.0/23 | 512 | ARIN | US | 29th Jul 1994 |
| 199.184.106.0/23 | 512 | ARIN | US | 29th Jul 1994 |
| 199.184.109.0/24 | 256 | ARIN | US | 29th Jul 1994 |
| 199.184.118.0/24 | 256 | ARIN | US | 29th Jul 1994 |
| 199.184.12.0/23 | 512 | ARIN | US | 8th Mar 1994 |
| 199.184.124.0/24 | 256 | ARIN | US | 29th Jul 1994 |
| 199.184.126.0/23 | 512 | ARIN | US | 16th Dec 2016 |
| 199.184.128.0/21 | 2k | ARIN | US | 19th Aug 2025 |
| 199.184.136.0/24 | 256 | ARIN | US | 11th Apr 1994 |
| 199.184.137.0/24 | 256 | ARIN | US | 11th Apr 1994 |
| 199.184.162.0/24 | 256 | ARIN | US | 14th Apr 1994 |
| 199.184.164.0/24 | 256 | ARIN | US | 14th Apr 1994 |
| 199.184.166.0/24 | 256 | ARIN | US | 14th Apr 1994 |
| 199.184.168.0/24 | 256 | ARIN | US | 14th Apr 1994 |
| 199.184.170.0/24 | 256 | ARIN | US | 14th Apr 1994 |
| 199.184.172.0/24 | 256 | ARIN | US | 14th Apr 1994 |
| 199.184.173.0/24 | 256 | ARIN | US | 14th Apr 1994 |
| 199.184.174.0/24 | 256 | ARIN | US | 14th Apr 1994 |
| 199.184.175.0/24 | 256 | ARIN | US | 14th Apr 1994 |
| 199.184.176.0/24 | 256 | ARIN | US | 14th Apr 1994 |
| 199.184.179.0/24 | 256 | ARIN | US | 14th Apr 1994 |
| 199.184.180.0/24 | 256 | ARIN | US | 14th Apr 1994 |
| 199.184.185.0/24 | 256 | ARIN | US | 29th Sept 2020 |
| 199.184.186.0/24 | 256 | ARIN | US | 14th Apr 1994 |
| 199.184.187.0/24 | 256 | ARIN | US | 14th Apr 1994 |
| 199.184.188.0/24 | 256 | ARIN | US | 14th Apr 1994 |
| 199.184.190.0/24 | 256 | ARIN | US | 14th Apr 1994 |
| 199.184.191.0/24 | 256 | ARIN | US | 14th Apr 1994 |
| 199.184.192.0/24 | 256 | ARIN | US | 14th Apr 1994 |
| 199.184.193.0/24 | 256 | ARIN | US | 15th Apr 1994 |
| 199.184.197.0/24 | 256 | ARIN | US | 15th Apr 1994 |
| 199.184.198.0/24 | 256 | ARIN | US | 15th Apr 1994 |
| 199.184.204.0/24 | 256 | ARIN | US | 15th Apr 1994 |
| 199.184.206.0/24 | 256 | ARIN | US | 15th Apr 1994 |