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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 the most unannounced blocks, largest first.
Unannounced blocks
85,356 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 205.236.227.0/24 | 256 | ARIN |  CA | 20th Oct 1995 |
| 205.236.228.0/24 | 256 | ARIN | CA | 20th Oct 1995 |
| 205.236.229.0/24 | 256 | ARIN | CA | 14th May 1996 |
| 205.236.232.0/24 | 256 | ARIN | CA | 12th Apr 1996 |
| 205.236.233.0/24 | 256 | ARIN | CA | 3rd Oct 1995 |
| 205.236.235.0/24 | 256 | ARIN | CA | 28th Sept 1995 |
| 205.236.236.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.236.237.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.236.238.0/23 | 512 | ARIN | CA | 25th Apr 1995 |
| 205.236.240.0/22 | 1k | ARIN | CA | 25th Apr 1995 |
| 205.236.244.0/24 | 256 | ARIN | CA | 28th Mar 2022 |
| 205.236.255.0/24 | 256 | ARIN |  US | 2nd Dec 2011 |
| 205.236.26.0/24 | 256 | ARIN | CA | 27th Nov 1995 |
| 205.236.28.0/23 | 512 | ARIN | CA | 22nd Nov 1995 |
| 205.236.30.0/24 | 256 | ARIN | CA | 22nd Nov 1995 |
| 205.236.32.0/23 | 512 | ARIN | CA | 10th Nov 1995 |
| 205.236.36.0/24 | 256 | ARIN | CA | 20th Nov 1995 |
| 205.236.37.0/24 | 256 | ARIN | CA | 6th Nov 1995 |
| 205.236.38.0/23 | 512 | ARIN | CA | 6th Nov 1995 |
| 205.236.40.0/24 | 256 | ARIN | CA | 7th Nov 1995 |
| 205.236.46.0/24 | 256 | ARIN | CA | 7th Nov 1995 |
| 205.236.47.0/24 | 256 | ARIN | CA | 27th Oct 1995 |
| 205.236.48.0/23 | 512 | ARIN | CA | 18th Oct 1995 |
| 205.236.50.0/24 | 256 | ARIN | CA | 23rd Oct 1995 |
| 205.236.51.0/24 | 256 | ARIN | US | 26th Sept 1996 |
| 205.236.52.0/24 | 256 | ARIN | CA | 23rd Oct 1995 |
| 205.236.53.0/24 | 256 | ARIN | CA | 19th Oct 1995 |
| 205.236.55.0/24 | 256 | ARIN | CA | 17th Oct 1995 |
| 205.236.57.0/24 | 256 | ARIN | CA | 17th Oct 1995 |
| 205.236.58.0/24 | 256 | ARIN | CA | 18th Jan 1996 |
| 205.236.59.0/24 | 256 | ARIN | CA | 17th Oct 1995 |
| 205.236.60.0/22 | 1k | ARIN | CA | 2nd Oct 1995 |
| 205.236.64.0/22 | 1k | ARIN | CA | 2nd Oct 1995 |
| 205.236.68.0/23 | 512 | ARIN | CA | 2nd Oct 1995 |
| 205.236.70.0/24 | 256 | ARIN | CA | 16th Oct 1995 |
| 205.236.72.0/24 | 256 | ARIN | CA | 17th Oct 1995 |
| 205.236.74.0/24 | 256 | ARIN | CA | 17th Oct 1995 |
| 205.236.75.0/24 | 256 | ARIN | US | 26th Sept 1996 |
| 205.236.82.0/24 | 256 | ARIN | CA | 19th Sept 1995 |
| 205.236.83.0/24 | 256 | ARIN | CA | 19th Sept 1995 |
| 205.236.88.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.236.90.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.236.91.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.236.92.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.236.96.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.236.97.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.236.98.0/24 | 256 | ARIN | CA | 11th Sept 1995 |
| 205.236.99.0/24 | 256 | ARIN | CA | 19th Dec 2022 |
| 205.237.1.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.237.2.0/24 | 256 | ARIN | CA | 25th Apr 1995 |