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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
84,968 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 137.191.216.0/22 | 1k | RIPE NCC |  IE | 1st Sept 1993 |
| 137.191.220.0/23 | 512 | RIPE NCC | IE | 1st Sept 1993 |
| 137.191.222.0/24 | 256 | RIPE NCC | IE | 1st Sept 1993 |
| 137.197.0.0/16 | 65.5k | ARIN |  US | 3rd Jan 1989 |
| 137.199.0.0/16 | 65.5k | ARIN | US | 3rd Jan 1990 |
| 137.20.0.0/16 | 65.5k | ARIN | US | 11th Oct 1989 |
| 137.206.0.0/16 | 65.5k | ARIN | US | 3rd Jan 1990 |
| 137.212.0.0/16 | 65.5k | ARIN | US | 9th Jan 1990 |
| 137.218.0.0/16 | 65.5k | RIPE NCC |  GB | 10th Jan 1990 |
| 137.223.0.0/16 | 65.5k | RIPE NCC |  DE | 10th Jan 1990 |
| 137.239.128.0/19 | 8.2k | ARIN | US | 16th Jan 1990 |
| 137.249.0.0/16 | 65.5k | ARIN | US | 20th Jan 1990 |
| 137.252.0.0/16 | 65.5k | ARIN | US | 26th Oct 2016 |
| 137.254.0.0/16 | 65.5k | ARIN | US | 17th Jan 1990 |
| 137.29.0.0/16 | 65.5k | ARIN | US | 19th Oct 1989 |
| 137.33.0.0/16 | 65.5k | RIPE NCC |  FI | 17th Oct 1989 |
| 137.34.0.0/16 | 65.5k | RIPE NCC |  CH | 1st Sept 1993 |
| 137.38.0.0/16 | 65.5k | ARIN | US | 25th Oct 1989 |
| 137.41.0.0/16 | 65.5k | ARIN | US | 2nd Jun 1997 |
| 137.42.0.0/16 | 65.5k | ARIN | US | 25th Oct 1989 |
| 137.44.128.0/17 | 32.8k | RIPE NCC | GB | 25th Oct 1989 |
| 137.44.64.0/19 | 8.2k | RIPE NCC | GB | 25th Oct 1989 |
| 137.44.96.0/20 | 4.1k | RIPE NCC | GB | 25th Oct 1989 |
| 137.46.0.0/16 | 65.5k | ARIN | US | 2nd Nov 1989 |
| 137.49.192.0/19 | 8.2k | ARIN | US | 1st Nov 1989 |
| 137.55.0.0/16 | 65.5k | RIPE NCC |  NL | 2nd Nov 1989 |
| 137.57.0.0/16 | 65.5k | ARIN | US | 5th Jul 1990 |
| 137.59.132.0/22 | 1k | APNIC |  IN | 3rd Feb 2016 |
| 137.59.136.0/22 | 1k | APNIC | IN | 3rd Feb 2016 |
| 137.59.140.0/22 | 1k | APNIC | IN | 3rd Feb 2016 |
| 137.59.156.0/22 | 1k | APNIC | IN | 4th Feb 2016 |
| 137.59.164.0/22 | 1k | APNIC | IN | 5th Feb 2016 |
| 137.59.168.0/22 | 1k | APNIC |  AU | 5th Feb 2016 |
| 137.59.176.0/22 | 1k | APNIC | IN | 5th Feb 2016 |
| 137.59.244.0/22 | 1k | APNIC | IN | 10th Feb 2016 |
| 137.59.28.0/22 | 1k | APNIC |  VN | 26th Oct 2015 |
| 137.59.36.0/22 | 1k | APNIC | VN | 26th Oct 2015 |
| 137.59.59.0/24 | 256 | APNIC |  CN | 9th Jun 2016 |
| 137.59.88.0/22 | 1k | APNIC | CN | 27th Oct 2015 |
| 137.60.0.0/16 | 65.5k | RIPE NCC |  SE | 5th Jul 1990 |
| 137.62.0.0/16 | 65.5k | RIPE NCC | CH | 1st Sept 1993 |
| 137.72.0.0/16 | 65.5k | ARIN | US | 6th Nov 1989 |
| 137.83.1.0/24 | 256 | ARIN | US | 9th Aug 2019 |
| 137.83.11.0/24 | 256 | ARIN | US | 26th Jun 2019 |
| 137.83.26.0/24 | 256 | ARIN | US | 28th Jan 2020 |
| 137.83.31.0/24 | 256 | ARIN |  CA | 8th May 2019 |
| 137.83.38.0/23 | 512 | ARIN | US | 23rd Oct 2020 |
| 137.83.58.0/23 | 512 | ARIN | US | 28th Jan 2019 |
| 137.83.73.0/24 | 256 | ARIN | US | 7th Apr 2020 |
| 137.83.74.0/23 | 512 | ARIN | US | 29th Mar 2019 |