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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 unannounced space registered through ARIN, largest first.
Unannounced blocks in United States
26,289 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.170.87.0/24 | 256 | ARIN |  US | 6th May 1992 |
| 192.170.88.0/24 | 256 | ARIN | US | 6th May 1992 |
| 192.170.89.0/24 | 256 | ARIN | US | 6th May 1992 |
| 192.170.90.0/24 | 256 | ARIN | US | 6th May 1992 |
| 192.170.91.0/24 | 256 | ARIN | US | 6th May 1992 |
| 192.170.92.0/23 | 512 | ARIN | US | 6th May 1992 |
| 192.170.94.0/23 | 512 | ARIN | US | 6th May 1992 |
| 192.170.96.0/24 | 256 | ARIN | US | 6th May 1992 |
| 192.170.97.0/24 | 256 | ARIN | US | 6th May 1992 |
| 192.170.98.0/23 | 512 | ARIN | US | 6th May 1992 |
| 192.171.224.0/19 | 8.2k | ARIN | US | 25th Apr 2013 |
| 192.171.24.0/21 | 2k | ARIN | US | 12th Feb 2016 |
| 192.171.7.0/24 | 256 | ARIN | US | 26th May 1992 |
| 192.172.222.0/24 | 256 | ARIN | US | 10th Jun 1992 |
| 192.172.223.0/24 | 256 | ARIN | US | 10th Jun 1992 |
| 192.172.225.0/24 | 256 | ARIN | US | 23rd Jun 1992 |
| 192.172.247.0/24 | 256 | ARIN | US | 1st Jul 2026 |
| 192.172.248.0/24 | 256 | ARIN | US | 10th Jun 1992 |
| 192.172.251.0/24 | 256 | ARIN | US | 11th Jun 1992 |
| 192.172.252.0/24 | 256 | ARIN | US | 11th Jun 1992 |
| 192.172.255.0/24 | 256 | ARIN | US | 16th Jul 2015 |
| 192.173.10.0/24 | 256 | ARIN | US | 29th Nov 2017 |
| 192.173.12.0/24 | 256 | ARIN | US | 22nd May 1992 |
| 192.173.8.0/24 | 256 | ARIN | US | 22nd May 1992 |
| 192.173.9.0/24 | 256 | ARIN | US | 22nd May 1992 |
| 192.174.0.0/23 | 512 | ARIN | US | 24th Mar 2015 |
| 192.174.70.0/23 | 512 | ARIN | US | 3rd Apr 2015 |
| 192.175.10.0/24 | 256 | ARIN | US | 28th May 1992 |
| 192.175.11.0/24 | 256 | ARIN | US | 28th May 1992 |
| 192.175.12.0/24 | 256 | ARIN | US | 28th May 1992 |
| 192.175.8.0/24 | 256 | ARIN | US | 28th May 1992 |
| 192.175.9.0/24 | 256 | ARIN | US | 28th May 1992 |
| 192.18.0.0/17 | 32.8k | ARIN | US | 9th Sept 1985 |
| 192.18.192.0/23 | 512 | ARIN | US | 9th Sept 1985 |
| 192.18.194.0/24 | 256 | ARIN | US | 9th Sept 1985 |
| 192.18.208.0/20 | 4.1k | ARIN | US | 9th Sept 1985 |
| 192.18.224.0/19 | 8.2k | ARIN | US | 9th Sept 1985 |
| 192.180.0.0/15 | 131k | ARIN | US | 26th Sept 2012 |
| 192.184.4.0/24 | 256 | ARIN | US | 8th Oct 1990 |
| 192.184.8.0/21 | 2k | ARIN | US | 7th Mar 2013 |
| 192.187.10.0/24 | 256 | ARIN | US | 19th Jun 1992 |
| 192.187.11.0/24 | 256 | ARIN | US | 19th Jun 1992 |
| 192.187.12.0/24 | 256 | ARIN | US | 19th Jun 1992 |
| 192.187.128.0/24 | 256 | ARIN | US | 30th Dec 1992 |
| 192.187.129.0/24 | 256 | ARIN | US | 8th Jan 1993 |
| 192.187.13.0/24 | 256 | ARIN | US | 19th Jun 1992 |
| 192.187.130.0/24 | 256 | ARIN | US | 17th Jul 1992 |
| 192.187.132.0/24 | 256 | ARIN | US | 8th Jan 1993 |
| 192.187.133.0/24 | 256 | ARIN | US | 8th Jan 1993 |
| 192.187.134.0/24 | 256 | ARIN | US | 17th Jul 1992 |