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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,256 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 198.51.236.0/23 | 512 | ARIN |  US | 10th Feb 1993 |
| 198.51.24.0/24 | 256 | ARIN | US | 26th Jan 1993 |
| 198.51.241.0/24 | 256 | ARIN | US | 12th Feb 1993 |
| 198.51.242.0/24 | 256 | ARIN | US | 12th Feb 1993 |
| 198.51.248.0/24 | 256 | ARIN | US | 12th Feb 1993 |
| 198.51.25.0/24 | 256 | ARIN | US | 26th Jan 1993 |
| 198.51.251.0/24 | 256 | ARIN | US | 22nd Aug 1995 |
| 198.51.252.0/24 | 256 | ARIN | US | 18th Feb 1993 |
| 198.51.253.0/24 | 256 | ARIN | US | 18th Feb 1993 |
| 198.51.26.0/23 | 512 | ARIN | US | 26th Jan 1993 |
| 198.51.28.0/23 | 512 | ARIN | US | 26th Jan 1993 |
| 198.51.3.0/24 | 256 | ARIN | US | 25th Jan 1993 |
| 198.51.30.0/24 | 256 | ARIN | US | 26th Jan 1993 |
| 198.51.31.0/24 | 256 | ARIN | US | 26th Jan 1993 |
| 198.51.32.0/23 | 512 | ARIN | US | 26th Jan 1993 |
| 198.51.34.0/24 | 256 | ARIN | US | 26th Jan 1993 |
| 198.51.35.0/24 | 256 | ARIN | US | 26th Jan 1993 |
| 198.51.36.0/24 | 256 | ARIN | US | 26th Jan 1993 |
| 198.51.37.0/24 | 256 | ARIN | US | 26th Jan 1993 |
| 198.51.38.0/24 | 256 | ARIN | US | 26th Jan 1993 |
| 198.51.39.0/24 | 256 | ARIN | US | 26th Jan 1993 |
| 198.51.40.0/23 | 512 | ARIN | US | 26th Jan 1993 |
| 198.51.46.0/24 | 256 | ARIN | US | 26th Jan 1993 |
| 198.51.47.0/24 | 256 | ARIN | US | 28th Jan 1993 |
| 198.51.48.0/24 | 256 | ARIN | US | 28th Jan 1993 |
| 198.51.53.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.54.0/23 | 512 | ARIN | US | 29th Jan 1993 |
| 198.51.56.0/23 | 512 | ARIN | US | 29th Jan 1993 |
| 198.51.58.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.59.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.60.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.62.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.63.0/24 | 256 | ARIN | US | 10th Sept 2013 |
| 198.51.64.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.65.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.66.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.67.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.68.0/24 | 256 | ARIN | US | 23rd Mar 1994 |
| 198.51.69.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.70.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.71.0/24 | 256 | LACNIC |  CO | 29th Jan 1993 |
| 198.51.73.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.74.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.77.0/24 | 256 | ARIN | US | 17th Jul 1996 |
| 198.51.78.0/23 | 512 | ARIN | US | 17th Jul 1996 |
| 198.51.80.0/23 | 512 | ARIN | US | 17th Jul 1996 |
| 198.51.89.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.90.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.52.16.0/21 | 2k | ARIN | US | 28th Jan 1993 |
| 198.52.24.0/23 | 512 | ARIN | US | 28th Jan 1993 |