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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,392 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 205.153.172.0/22 | 1k | ARIN |  US | 8th Jun 1995 |
| 205.153.184.0/22 | 1k | ARIN | US | 13th Jun 1995 |
| 205.153.188.0/22 | 1k | ARIN | US | 14th Jun 1995 |
| 205.153.192.0/22 | 1k | ARIN | US | 15th Jun 1995 |
| 205.153.196.0/22 | 1k | ARIN | US | 27th Oct 1997 |
| 205.153.20.0/22 | 1k | ARIN | US | 22nd Mar 1995 |
| 205.153.200.0/22 | 1k | ARIN | US | 15th Jun 1995 |
| 205.153.212.0/22 | 1k | ARIN | US | 19th Jun 1995 |
| 205.153.216.0/22 | 1k | ARIN | US | 27th Jun 1995 |
| 205.153.228.0/23 | 512 | ARIN |  CA | 1st Jul 2025 |
| 205.153.231.0/24 | 256 | ARIN | US | 29th Jun 1995 |
| 205.153.236.0/22 | 1k | ARIN | US | 6th Jul 1995 |
| 205.153.24.0/22 | 1k | ARIN | US | 24th Mar 1995 |
| 205.153.244.0/22 | 1k | ARIN | US | 12th Jul 1995 |
| 205.153.248.0/22 | 1k | ARIN | US | 12th Jul 1995 |
| 205.153.4.0/22 | 1k | ARIN | US | 21st Mar 1995 |
| 205.153.40.0/22 | 1k | ARIN | US | 6th Apr 1995 |
| 205.153.56.0/22 | 1k | ARIN | US | 25th Apr 1995 |
| 205.153.64.0/22 | 1k | ARIN | US | 1st May 1995 |
| 205.153.68.0/22 | 1k | ARIN | US | 1st May 1995 |
| 205.153.72.0/22 | 1k | ARIN | US | 2nd May 1995 |
| 205.153.76.0/22 | 1k | ARIN | US | 5th May 1995 |
| 205.156.192.0/18 | 16.4k | ARIN | US | 17th Mar 1995 |
| 205.159.0.0/24 | 256 | ARIN | US | 9th Mar 1995 |
| 205.159.10.0/24 | 256 | ARIN | US | 10th Mar 1995 |
| 205.159.100.0/24 | 256 | ARIN | US | 4th Apr 1995 |
| 205.159.102.0/24 | 256 | ARIN | US | 6th Apr 1995 |
| 205.159.104.0/24 | 256 | ARIN | US | 10th Apr 1995 |
| 205.159.105.0/24 | 256 | ARIN | US | 11th Apr 1995 |
| 205.159.106.0/24 | 256 | ARIN | US | 17th Apr 1995 |
| 205.159.107.0/24 | 256 | ARIN | US | 17th Apr 1995 |
| 205.159.108.0/24 | 256 | ARIN | US | 20th Apr 1995 |
| 205.159.109.0/24 | 256 | ARIN | US | 24th Apr 1995 |
| 205.159.11.0/24 | 256 | ARIN | US | 10th Mar 1995 |
| 205.159.110.0/24 | 256 | ARIN | US | 24th Apr 1995 |
| 205.159.111.0/24 | 256 | ARIN | US | 24th Apr 1995 |
| 205.159.112.0/24 | 256 | ARIN | US | 24th Apr 1995 |
| 205.159.113.0/24 | 256 | ARIN | US | 24th Apr 1995 |
| 205.159.114.0/24 | 256 | ARIN | US | 16th Aug 1995 |
| 205.159.116.0/24 | 256 | ARIN | US | 26th Apr 1995 |
| 205.159.119.0/24 | 256 | ARIN | US | 28th Apr 1995 |
| 205.159.122.0/24 | 256 | ARIN | US | 1st May 1995 |
| 205.159.123.0/24 | 256 | ARIN | US | 1st May 1995 |
| 205.159.124.0/24 | 256 | ARIN | US | 1st May 1995 |
| 205.159.126.0/24 | 256 | ARIN | US | 1st May 1995 |
| 205.159.127.0/24 | 256 | ARIN | US | 1st May 1995 |
| 205.159.129.0/24 | 256 | ARIN | US | 5th May 1995 |
| 205.159.13.0/24 | 256 | ARIN | US | 10th Mar 1995 |
| 205.159.130.0/24 | 256 | ARIN | US | 5th May 1995 |
| 205.159.131.0/24 | 256 | ARIN | US | 8th May 1995 |