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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,124 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.153.20.0/24 | 256 | ARIN |  US | 31st Mar 1992 |
| 192.153.200.0/24 | 256 | ARIN | US | 25th Nov 1991 |
| 192.153.201.0/24 | 256 | ARIN | US | 25th Nov 1991 |
| 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 |
| 192.153.217.0/24 | 256 | ARIN |  CA | 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 |
| 192.153.220.0/24 | 256 | ARIN | CA | 13th Apr 1992 |
| 192.153.221.0/24 | 256 | APNIC |  PH | 7th Feb 2011 |
| 192.153.222.0/23 | 512 | APNIC | PH | 7th Feb 2011 |
| 192.153.224.0/22 | 1k | APNIC | PH | 7th Feb 2011 |
| 192.153.228.0/24 | 256 | APNIC | PH | 7th Feb 2011 |
| 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 |
| 192.153.251.0/24 | 256 | APNIC |  SG | 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 |
| 192.153.3.0/24 | 256 | RIPE NCC |  GB | 27th Mar 1992 |
| 192.153.42.0/24 | 256 | ARIN | US | 10th Aug 1992 |