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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 in United States
26,295 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.53.0.0/23 | 512 | ARIN |  US | 27th Mar 1989 |
| 192.53.100.0/23 | 512 | ARIN | US | 27th Mar 1989 |
| 192.53.102.0/24 | 256 | ARIN | US | 27th Mar 1989 |
| 192.53.105.0/24 | 256 | ARIN | US | 27th Mar 1989 |
| 192.53.106.0/23 | 512 | ARIN | US | 27th Mar 1989 |
| 192.53.108.0/22 | 1k | ARIN | US | 27th Mar 1989 |
| 192.53.128.0/21 | 2k | ARIN | US | 27th Mar 1989 |
| 192.53.144.0/21 | 2k | ARIN | US | 27th Mar 1989 |
| 192.53.152.0/22 | 1k | ARIN | US | 27th Mar 1989 |
| 192.53.156.0/24 | 256 | ARIN | US | 27th Mar 1989 |
| 192.53.157.0/24 | 256 | ARIN | US | 27th Mar 1989 |
| 192.53.158.0/23 | 512 | ARIN | US | 27th Mar 1989 |
| 192.53.16.0/24 | 256 | ARIN | US | 27th Mar 1989 |
| 192.53.17.0/24 | 256 | ARIN | US | 27th Mar 1989 |
| 192.53.176.0/22 | 1k | ARIN | US | 27th Mar 1989 |
| 192.53.18.0/23 | 512 | ARIN | US | 27th Mar 1989 |
| 192.53.180.0/23 | 512 | ARIN | US | 27th Mar 1989 |
| 192.53.182.0/24 | 256 | ARIN | US | 27th Mar 1989 |
| 192.53.183.0/24 | 256 | ARIN | US | 27th Mar 1989 |
| 192.53.184.0/23 | 512 | ARIN | US | 27th Mar 1989 |
| 192.53.186.0/24 | 256 | ARIN | US | 27th Mar 1989 |
| 192.53.188.0/22 | 1k | ARIN | US | 27th Mar 1989 |
| 192.53.192.0/21 | 2k | ARIN | US | 27th Mar 1989 |
| 192.53.2.0/24 | 256 | ARIN | US | 27th Mar 1989 |
| 192.53.20.0/22 | 1k | ARIN | US | 27th Mar 1989 |
| 192.53.200.0/23 | 512 | ARIN | US | 27th Mar 1989 |
| 192.53.202.0/24 | 256 | ARIN | US | 27th Mar 1989 |
| 192.53.203.0/24 | 256 | ARIN | US | 27th Mar 1989 |
| 192.53.204.0/22 | 1k | ARIN | US | 27th Mar 1989 |
| 192.53.208.0/20 | 4.1k | ARIN | US | 27th Mar 1989 |
| 192.53.224.0/20 | 4.1k | ARIN | US | 27th Mar 1989 |
| 192.53.24.0/21 | 2k | ARIN | US | 27th Mar 1989 |
| 192.53.240.0/21 | 2k | ARIN | US | 27th Mar 1989 |
| 192.53.248.0/22 | 1k | ARIN | US | 27th Mar 1989 |
| 192.53.252.0/23 | 512 | ARIN | US | 27th Mar 1989 |
| 192.53.254.0/24 | 256 | ARIN | US | 27th Mar 1989 |
| 192.53.255.0/24 | 256 | ARIN | US | 27th Mar 1989 |
| 192.53.3.0/24 | 256 | ARIN | US | 27th Mar 1989 |
| 192.53.32.0/23 | 512 | ARIN | US | 27th Mar 1989 |
| 192.53.34.0/24 | 256 | ARIN | US | 27th Mar 1989 |
| 192.53.35.0/24 | 256 | ARIN | US | 4th Jun 1992 |
| 192.53.36.0/23 | 512 | ARIN | US | 27th Mar 1989 |
| 192.53.38.0/24 | 256 | ARIN | US | 27th Mar 1989 |
| 192.53.39.0/24 | 256 | ARIN | US | 27th Mar 1989 |
| 192.53.4.0/22 | 1k | ARIN | US | 27th Mar 1989 |
| 192.53.48.0/20 | 4.1k | ARIN | US | 27th Mar 1989 |
| 192.53.72.0/21 | 2k | ARIN | US | 27th Mar 1989 |
| 192.53.8.0/21 | 2k | ARIN | US | 27th Mar 1989 |
| 192.53.96.0/24 | 256 | ARIN | US | 27th Mar 1989 |
| 192.53.98.0/23 | 512 | ARIN | US | 27th Mar 1989 |