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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 unannounced space registered through ARIN, largest first.
Unannounced blocks registered through ARIN
30,434 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 161.144.0.0/16 | 65.5k | ARIN |  US | 16th Oct 1992 |
| 161.145.104.0/21 | 2k | ARIN | US | 22nd Oct 1992 |
| 161.145.112.0/20 | 4.1k | ARIN | US | 22nd Oct 1992 |
| 161.145.64.0/19 | 8.2k | ARIN | US | 22nd Oct 1992 |
| 161.161.0.0/16 | 65.5k | ARIN | US | 31st Dec 1992 |
| 161.182.0.0/16 | 65.5k | ARIN | US | 13th Jan 1993 |
| 161.183.0.0/16 | 65.5k | ARIN | US | 13th Jan 1993 |
| 161.186.0.0/16 | 65.5k | ARIN | US | 15th Jan 1993 |
| 161.187.0.0/16 | 65.5k | ARIN |  CA | 15th Jan 1993 |
| 161.188.192.0/21 | 2k | ARIN | US | 29th Dec 2020 |
| 161.188.200.0/22 | 1k | ARIN | US | 29th Dec 2020 |
| 161.188.205.0/24 | 256 | ARIN | US | 29th Dec 2020 |
| 161.188.206.0/23 | 512 | ARIN | US | 29th Dec 2020 |
| 161.188.208.0/23 | 512 | ARIN | US | 29th Dec 2020 |
| 161.188.211.0/24 | 256 | ARIN | US | 21st Jan 1993 |
| 161.188.213.0/24 | 256 | ARIN | US | 29th Dec 2020 |
| 161.188.214.0/23 | 512 | ARIN | US | 29th Dec 2020 |
| 161.188.224.0/20 | 4.1k | ARIN | US | 29th Dec 2020 |
| 161.188.248.0/22 | 1k | ARIN | US | 29th Dec 2020 |
| 161.188.252.0/23 | 512 | ARIN | US | 29th Dec 2020 |
| 161.188.254.0/24 | 256 | ARIN | US | 29th Dec 2020 |
| 161.188.255.0/24 | 256 | ARIN | US | 21st Jan 1993 |
| 161.192.0.0/16 | 65.5k | ARIN | US | 21st Jan 1993 |
| 161.194.0.0/16 | 65.5k | ARIN | US | 25th Jan 1993 |
| 161.199.1.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.10.0/24 | 256 | ARIN | US | 8th Aug 2019 |
| 161.199.105.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.106.0/23 | 512 | ARIN | US | 29th Jan 1993 |
| 161.199.108.0/22 | 1k | ARIN | US | 29th Jan 1993 |
| 161.199.11.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.113.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.114.0/23 | 512 | ARIN | US | 29th Jan 1993 |
| 161.199.116.0/23 | 512 | ARIN | US | 29th Jan 1993 |
| 161.199.118.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.12.0/24 | 256 | ARIN | US | 18th Aug 2020 |
| 161.199.120.0/22 | 1k | ARIN | US | 29th Jan 1993 |
| 161.199.131.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.136.0/22 | 1k | ARIN | US | 24th May 2019 |
| 161.199.14.0/24 | 256 | ARIN | US | 18th Aug 2020 |
| 161.199.145.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.146.0/23 | 512 | ARIN | US | 29th Jan 1993 |
| 161.199.148.0/22 | 1k | ARIN | US | 29th Jan 1993 |
| 161.199.15.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.154.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.157.0/24 | 256 | ARIN | US | 3rd Apr 2025 |
| 161.199.158.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.17.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.173.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.174.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.175.0/24 | 256 | ARIN |  BS | 18th Sept 2019 |