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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 in United States
27,007 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.153.202.0/24 | 256 | ARIN |  US | 25th Nov 1991 |
| 192.153.203.0/24 | 256 | ARIN | US | 25th Nov 1991 |
| 192.153.204.0/24 | 256 | ARIN | US | 25th Nov 1991 |
| 192.153.205.0/24 | 256 | ARIN | US | 25th Nov 1991 |
| 192.153.206.0/24 | 256 | ARIN | US | 25th Nov 1991 |
| 192.153.207.0/24 | 256 | ARIN | US | 25th Nov 1991 |
| 192.153.208.0/24 | 256 | ARIN | US | 25th Nov 1991 |
| 192.153.209.0/24 | 256 | ARIN | US | 25th Nov 1991 |
| 192.153.21.0/24 | 256 | ARIN | US | 31st Mar 1992 |
| 192.153.210.0/24 | 256 | ARIN | US | 25th Nov 1991 |
| 192.153.211.0/24 | 256 | ARIN | US | 12th May 1992 |
| 192.153.212.0/24 | 256 | ARIN | US | 13th Apr 1992 |
| 192.153.214.0/24 | 256 | ARIN | US | 13th Apr 1992 |
| 192.153.215.0/24 | 256 | ARIN | US | 13th Apr 1992 |
| 192.153.216.0/24 | 256 | ARIN | US | 13th Apr 1992 |
| 192.153.218.0/24 | 256 | ARIN | US | 13th Apr 1992 |
| 192.153.219.0/24 | 256 | ARIN | US | 13th Apr 1992 |
| 192.153.22.0/24 | 256 | ARIN | US | 31st Mar 1992 |
| 192.153.229.0/24 | 256 | ARIN | US | 14th Apr 1992 |
| 192.153.23.0/24 | 256 | ARIN | US | 31st Mar 1992 |
| 192.153.230.0/24 | 256 | ARIN | US | 14th Apr 1992 |
| 192.153.231.0/24 | 256 | ARIN | US | 14th Apr 1992 |
| 192.153.232.0/24 | 256 | ARIN | US | 14th Apr 1992 |
| 192.153.233.0/24 | 256 | ARIN | US | 14th Apr 1992 |
| 192.153.234.0/24 | 256 | ARIN | US | 14th Apr 1992 |
| 192.153.235.0/24 | 256 | ARIN | US | 14th Apr 1992 |
| 192.153.236.0/24 | 256 | ARIN | US | 14th Apr 1992 |
| 192.153.237.0/24 | 256 | ARIN | US | 14th Apr 1992 |
| 192.153.238.0/24 | 256 | ARIN | US | 14th Apr 1992 |
| 192.153.239.0/24 | 256 | ARIN | US | 14th Apr 1992 |
| 192.153.24.0/24 | 256 | ARIN | US | 19th Dec 2019 |
| 192.153.243.0/24 | 256 | ARIN | US | 14th Apr 1992 |
| 192.153.248.0/24 | 256 | ARIN | US | 15th Apr 1992 |
| 192.153.249.0/24 | 256 | ARIN | US | 15th Apr 1992 |
| 192.153.25.0/24 | 256 | ARIN | US | 18th Jun 2015 |
| 192.153.250.0/24 | 256 | ARIN | US | 15th Apr 1992 |
| 192.153.252.0/24 | 256 | ARIN | US | 15th Apr 1992 |
| 192.153.253.0/24 | 256 | ARIN | US | 15th Apr 1992 |
| 192.153.42.0/24 | 256 | ARIN | US | 10th Aug 1992 |
| 192.153.43.0/24 | 256 | ARIN | US | 10th Aug 1992 |
| 192.153.44.0/24 | 256 | ARIN | US | 12th Apr 1993 |
| 192.153.45.0/24 | 256 | ARIN | US | 10th Aug 1992 |
| 192.153.47.0/24 | 256 | ARIN | US | 5th May 1992 |
| 192.153.48.0/24 | 256 | ARIN | US | 31st Mar 1992 |
| 192.153.49.0/24 | 256 | ARIN | US | 10th Aug 1992 |
| 192.153.50.0/24 | 256 | ARIN | US | 10th Aug 1992 |
| 192.153.54.0/24 | 256 | ARIN | US | 24th Jul 1992 |
| 192.153.55.0/24 | 256 | ARIN | US | 24th Jul 1992 |
| 192.153.56.0/24 | 256 | ARIN | US | 31st Mar 1992 |
| 192.153.7.0/24 | 256 | ARIN | US | 30th Mar 1992 |