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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,356 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 208.103.150.0/24 | 256 | ARIN |  US | 30th Jul 2018 |
| 208.103.151.0/24 | 256 | ARIN | US | 17th Dec 2021 |
| 208.103.153.0/24 | 256 | ARIN | US | 6th Jul 2016 |
| 208.103.160.0/24 | 256 | ARIN | US | 1st Nov 2021 |
| 208.103.182.0/24 | 256 | ARIN | US | 13th Apr 2018 |
| 208.103.183.0/24 | 256 | ARIN | US | 2nd Apr 2026 |
| 208.114.0.0/19 | 8.2k | ARIN | US | 25th Apr 2006 |
| 208.116.64.0/18 | 16.4k | ARIN | US | 25th May 2007 |
| 208.117.128.0/18 | 16.4k | ARIN | US | 9th May 2006 |
| 208.117.93.0/24 | 256 | ARIN | US | 30th Mar 2016 |
| 208.122.10.0/24 | 256 | ARIN | US | 29th Jul 2026 |
| 208.122.11.0/24 | 256 | RIPE NCC |  AE | 12th May 2006 |
| 208.122.12.0/23 | 512 | ARIN | US | 22nd Jun 2026 |
| 208.122.23.0/24 | 256 | RIPE NCC |  AZ | 12th May 2006 |
| 208.122.240.0/20 | 4.1k | ARIN |  CA | 3rd Aug 2009 |
| 208.122.4.0/24 | 256 | ARIN | US | 8th Oct 2025 |
| 208.122.9.0/24 | 256 | ARIN | US | 12th May 2006 |
| 208.123.176.0/21 | 2k | ARIN | US | 11th Jun 2025 |
| 208.123.209.0/24 | 256 | ARIN | US | 21st Apr 2008 |
| 208.128.0.0/15 | 131k | ARIN | US | 27th Mar 1996 |
| 208.132.0.0/18 | 16.4k | ARIN | US | 27th Mar 1996 |
| 208.132.128.0/17 | 32.8k | ARIN | US | 27th Mar 1996 |
| 208.132.64.0/19 | 8.2k | ARIN | US | 27th Mar 1996 |
| 208.132.96.0/19 | 8.2k | ARIN | US | 27th Mar 1996 |
| 208.138.0.0/20 | 4.1k | ARIN | US | 27th Mar 1996 |
| 208.138.128.0/19 | 8.2k | ARIN | US | 27th Mar 1996 |
| 208.138.160.0/21 | 2k | ARIN | US | 27th Mar 1996 |
| 208.138.176.0/20 | 4.1k | ARIN | US | 27th Mar 1996 |
| 208.138.64.0/18 | 16.4k | ARIN | US | 27th Mar 1996 |
| 208.139.0.0/16 | 65.5k | ARIN | US | 27th Mar 1996 |
| 208.140.0.0/14 | 262k | ARIN | US | 27th Mar 1996 |
| 208.152.0.0/14 | 262k | ARIN | US | 27th Mar 1996 |
| 208.157.192.0/18 | 16.4k | ARIN | US | 27th Mar 1996 |
| 208.162.0.0/16 | 65.5k | ARIN | US | 27th Mar 1996 |
| 208.164.0.0/15 | 131k | ARIN | US | 27th Mar 1996 |
| 208.166.128.0/17 | 32.8k | ARIN | US | 27th Mar 1996 |
| 208.166.32.0/20 | 4.1k | ARIN | US | 27th Mar 1996 |
| 208.166.48.0/20 | 4.1k | RIPE NCC |  DE | 1st Aug 2006 |
| 208.168.128.0/18 | 16.4k | ARIN | US | 27th Mar 1996 |
| 208.39.0.0/17 | 32.8k | ARIN | US | 25th Jun 1999 |
| 208.52.136.0/24 | 256 | ARIN | US | 18th Nov 2020 |
| 208.52.143.0/24 | 256 | ARIN | US | 8th Dec 2016 |
| 208.52.169.0/24 | 256 | ARIN | US | 1st Jun 2020 |
| 208.52.184.0/24 | 256 | ARIN | US | 26th Jun 2024 |
| 208.52.192.0/18 | 16.4k | ARIN | US | 21st May 2002 |
| 208.64.100.0/22 | 1k | ARIN | US | 16th Dec 2005 |
| 208.64.120.0/21 | 2k | ARIN | US | 22nd Dec 2005 |
| 208.64.152.0/24 | 256 | ARIN | US | 24th Apr 2020 |
| 208.64.188.0/22 | 1k | ARIN | US | 4th Jan 2006 |
| 208.64.204.0/22 | 1k | ARIN | US | 18th Jan 2006 |