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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 Kingdom
2,628 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 46.43.128.0/18 | 16.4k | RIPE NCC |  GB | 17th Aug 2010 |
| 5.100.168.0/21 | 2k | RIPE NCC | GB | 26th Jun 2012 |
| 5.133.80.0/22 | 1k | RIPE NCC | GB | 9th Nov 2018 |
| 5.144.152.0/24 | 256 | RIPE NCC | GB | 12th Jul 2012 |
| 5.144.154.0/23 | 512 | RIPE NCC | GB | 12th Jul 2012 |
| 5.154.232.0/24 | 256 | RIPE NCC | GB | 19th Jul 2012 |
| 5.182.76.0/22 | 1k | RIPE NCC | GB | 5th Apr 2019 |
| 5.183.112.0/22 | 1k | RIPE NCC | GB | 10th Apr 2019 |
| 5.253.108.0/22 | 1k | RIPE NCC | GB | 8th Feb 2019 |
| 5.45.48.0/21 | 2k | RIPE NCC | GB | 25th May 2012 |
| 5.63.18.0/24 | 256 | RIPE NCC | GB | 15th Jan 2024 |
| 51.130.0.0/16 | 65.5k | RIPE NCC | GB | 1st Sept 1993 |
| 51.147.0.0/16 | 65.5k | RIPE NCC | GB | 1st Sept 1993 |
| 51.2.0.0/16 | 65.5k | RIPE NCC | GB | 1st Sept 1993 |
| 51.234.0.0/16 | 65.5k | RIPE NCC | GB | 1st Sept 1993 |
| 51.238.0.0/15 | 131k | RIPE NCC | GB | 1st Sept 1993 |
| 51.242.0.0/15 | 131k | RIPE NCC | GB | 1st Sept 1993 |
| 51.246.0.0/15 | 131k | RIPE NCC | GB | 1st Sept 1993 |
| 51.251.0.0/16 | 65.5k | RIPE NCC | GB | 1st Sept 1993 |
| 51.33.0.0/16 | 65.5k | RIPE NCC | GB | 1st Sept 1993 |
| 51.62.0.0/15 | 131k | RIPE NCC | GB | 1st Sept 1993 |
| 51.65.0.0/16 | 65.5k | RIPE NCC | GB | 1st Sept 1993 |
| 51.66.0.0/15 | 131k | RIPE NCC | GB | 1st Sept 1993 |
| 51.71.0.0/16 | 65.5k | RIPE NCC | GB | 1st Sept 1993 |
| 62.130.0.0/16 | 65.5k | RIPE NCC | GB | 18th Sept 2000 |
| 62.136.0.0/16 | 65.5k | RIPE NCC | GB | 6th May 1997 |
| 62.137.0.0/16 | 65.5k | RIPE NCC | GB | 21st May 1999 |
| 62.169.157.0/24 | 256 | RIPE NCC | GB | 1st Aug 2000 |
| 62.222.0.0/16 | 65.5k | RIPE NCC | GB | 27th Oct 2000 |
| 62.233.50.0/24 | 256 | RIPE NCC | GB | 7th Jan 2025 |
| 62.80.64.0/19 | 8.2k | RIPE NCC | GB | 22nd Jun 2000 |
| 64.239.120.0/23 | 512 | RIPE NCC | GB | 25th Sept 2001 |
| 64.254.88.0/21 | 2k | RIPE NCC | GB | 26th May 2004 |
| 65.181.117.0/24 | 256 | RIPE NCC | GB | 9th Mar 2011 |
| 66.242.48.0/23 | 512 | RIPE NCC | GB | 4th Mar 2002 |
| 66.248.237.0/24 | 256 | ARIN | GB | 19th Dec 2019 |
| 74.209.175.0/24 | 256 | RIPE NCC | GB | 19th May 2009 |
| 77.233.128.0/19 | 8.2k | RIPE NCC | GB | 19th Dec 2006 |
| 77.72.200.0/21 | 2k | RIPE NCC | GB | 19th Feb 2007 |
| 77.73.72.0/21 | 2k | RIPE NCC | GB | 8th Mar 2007 |
| 77.81.90.0/23 | 512 | RIPE NCC | GB | 15th Feb 2007 |
| 77.92.64.0/19 | 8.2k | RIPE NCC | GB | 7th May 2007 |
| 78.108.114.0/24 | 256 | RIPE NCC | GB | 23rd Jun 2026 |
| 78.143.252.0/23 | 512 | RIPE NCC | GB | 22nd Aug 2007 |
| 78.41.140.0/24 | 256 | RIPE NCC | GB | 12th Jan 2024 |
| 78.41.143.0/24 | 256 | RIPE NCC | GB | 12th Jan 2024 |
| 79.110.160.0/22 | 1k | RIPE NCC | GB | 10th Aug 2018 |
| 79.110.172.0/22 | 1k | RIPE NCC | GB | 10th Aug 2018 |
| 79.135.100.0/22 | 1k | RIPE NCC | GB | 31st Oct 2007 |
| 79.170.192.0/24 | 256 | RIPE NCC | GB | 2nd Oct 2007 |