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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
26,302 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 198.153.146.0/24 | 256 | ARIN |  US | 9th Aug 1993 |
| 198.153.147.0/24 | 256 | ARIN | US | 9th Aug 1993 |
| 198.153.149.0/24 | 256 | ARIN | US | 9th Aug 1993 |
| 198.153.150.0/24 | 256 | ARIN | US | 10th Aug 1993 |
| 198.153.151.0/24 | 256 | ARIN | US | 10th Aug 1993 |
| 198.153.164.0/24 | 256 | ARIN | US | 10th Aug 1993 |
| 198.153.165.0/24 | 256 | ARIN | US | 11th Aug 1993 |
| 198.153.166.0/23 | 512 | ARIN | US | 11th Aug 1993 |
| 198.153.168.0/24 | 256 | ARIN | US | 11th Aug 1993 |
| 198.153.170.0/24 | 256 | ARIN | US | 11th Aug 1993 |
| 198.153.171.0/24 | 256 | ARIN | US | 11th Aug 1993 |
| 198.153.172.0/22 | 1k | ARIN | US | 11th Aug 1993 |
| 198.153.176.0/21 | 2k | ARIN | US | 11th Aug 1993 |
| 198.153.190.0/23 | 512 | ARIN | US | 11th Aug 1993 |
| 198.153.196.0/24 | 256 | ARIN | US | 11th Aug 1993 |
| 198.153.197.0/24 | 256 | ARIN | US | 12th Aug 1993 |
| 198.153.198.0/24 | 256 | ARIN | US | 12th Aug 1993 |
| 198.153.199.0/24 | 256 | ARIN | US | 12th Aug 1993 |
| 198.153.200.0/24 | 256 | ARIN | US | 13th Aug 1993 |
| 198.153.202.0/24 | 256 | ARIN | US | 13th Aug 1993 |
| 198.153.203.0/24 | 256 | ARIN | US | 13th Aug 1993 |
| 198.153.204.0/24 | 256 | ARIN | US | 13th Aug 1993 |
| 198.153.205.0/24 | 256 | ARIN | US | 17th Aug 1993 |
| 198.153.206.0/24 | 256 | ARIN | US | 17th Aug 1993 |
| 198.153.207.0/24 | 256 | ARIN | US | 22nd Oct 2013 |
| 198.153.208.0/24 | 256 | ARIN | US | 2nd Jul 2026 |
| 198.153.209.0/24 | 256 | ARIN | US | 2nd Jul 2026 |
| 198.153.210.0/24 | 256 | ARIN | US | 8th Jul 2026 |
| 198.153.211.0/24 | 256 | ARIN | US | 2nd Jul 2026 |
| 198.153.214.0/24 | 256 | ARIN | US | 4th Aug 2026 |
| 198.153.218.0/24 | 256 | ARIN | US | 2nd Jul 2026 |
| 198.153.220.0/24 | 256 | ARIN | US | 17th Aug 1993 |
| 198.153.221.0/24 | 256 | ARIN | US | 17th Aug 1993 |
| 198.153.222.0/24 | 256 | ARIN | US | 18th Aug 1993 |
| 198.153.232.0/24 | 256 | ARIN | US | 20th Aug 1993 |
| 198.153.233.0/24 | 256 | ARIN | US | 20th Aug 1993 |
| 198.153.234.0/24 | 256 | ARIN | US | 20th Aug 1993 |
| 198.153.235.0/24 | 256 | ARIN | US | 20th Aug 1993 |
| 198.153.236.0/24 | 256 | ARIN | US | 20th Aug 1993 |
| 198.153.237.0/24 | 256 | ARIN | US | 20th Aug 1993 |
| 198.153.246.0/24 | 256 | ARIN | US | 20th Aug 1993 |
| 198.153.247.0/24 | 256 | ARIN | US | 20th Aug 1993 |
| 198.153.248.0/24 | 256 | ARIN | US | 20th Aug 1993 |
| 198.153.249.0/24 | 256 | ARIN | US | 20th Aug 1993 |
| 198.153.250.0/24 | 256 | ARIN | US | 20th Aug 1993 |
| 198.153.251.0/24 | 256 | ARIN | US | 20th Aug 1993 |
| 198.153.252.0/24 | 256 | ARIN | US | 20th Aug 1993 |
| 198.153.254.0/24 | 256 | ARIN | US | 30th Aug 1993 |
| 198.153.32.0/20 | 4.1k | ARIN | US | 3rd May 1993 |
| 198.153.48.0/21 | 2k | ARIN | US | 3rd May 1993 |