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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,201 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.31.168.0/23 | 512 | RIPE NCC |  NL | 7th Aug 1987 |
| 192.31.170.0/24 | 256 | RIPE NCC | NL | 7th Aug 1987 |
| 192.31.171.0/24 | 256 | RIPE NCC | NL | 7th Aug 1987 |
| 192.31.173.0/24 | 256 | ARIN |  US | 13th Jun 1988 |
| 192.31.175.0/24 | 256 | ARIN | US | 21st Aug 1987 |
| 192.31.176.0/24 | 256 | ARIN | US | 21st Aug 1987 |
| 192.31.181.0/24 | 256 | ARIN | US | 3rd Nov 1987 |
| 192.31.184.0/22 | 1k | ARIN | US | 20th Nov 2012 |
| 192.31.191.0/24 | 256 | ARIN | US | 3rd Nov 1987 |
| 192.31.194.0/24 | 256 | ARIN | US | 14th May 1990 |
| 192.31.195.0/24 | 256 | ARIN | US | 16th May 1990 |
| 192.31.197.0/24 | 256 | APNIC |  JP | 28th Aug 1987 |
| 192.31.207.0/24 | 256 | ARIN | US | 21st Nov 1986 |
| 192.31.208.0/23 | 512 | ARIN | US | 2nd Jul 2014 |
| 192.31.211.0/24 | 256 | RIPE NCC |  FR | 3rd Sept 1987 |
| 192.31.212.0/23 | 512 | ARIN | US | 14th Jul 2022 |
| 192.31.214.0/24 | 256 | ARIN | US | 25th Apr 2014 |
| 192.31.217.0/24 | 256 | ARIN | US | 8th Sept 1987 |
| 192.31.218.0/24 | 256 | ARIN | US | 8th Sept 1987 |
| 192.31.219.0/24 | 256 | ARIN | US | 8th Sept 1987 |
| 192.31.220.0/24 | 256 | ARIN | US | 8th Sept 1987 |
| 192.31.221.0/24 | 256 | ARIN | US | 8th Sept 1987 |
| 192.31.223.0/24 | 256 | ARIN | US | 17th Aug 1988 |
| 192.31.229.0/24 | 256 | RIPE NCC |  TR | 11th Sept 1987 |
| 192.31.230.0/24 | 256 | ARIN | US | 11th Sept 1987 |
| 192.31.232.0/24 | 256 | ARIN | US | 16th Sept 1987 |
| 192.31.233.0/24 | 256 | ARIN | US | 19th Sept 1987 |
| 192.31.235.0/24 | 256 | ARIN | US | 22nd Sept 1987 |
| 192.31.24.0/24 | 256 | ARIN | US | 22nd Apr 1987 |
| 192.31.240.0/24 | 256 | ARIN | US | 23rd Sept 1987 |
| 192.31.244.0/24 | 256 | ARIN | US | 30th Apr 2014 |
| 192.31.246.0/24 | 256 | ARIN | US | 22nd Mar 2017 |
| 192.31.247.0/24 | 256 | ARIN | US | 9th Oct 1987 |
| 192.31.249.0/24 | 256 | ARIN | US | 4th Oct 1987 |
| 192.31.25.0/24 | 256 | ARIN | US | 9th Feb 1988 |
| 192.31.250.0/24 | 256 | ARIN | US | 9th Oct 1987 |
| 192.31.252.0/24 | 256 | RIPE NCC | FR | 27th Oct 1987 |
| 192.31.255.0/24 | 256 | ARIN | US | 1st Jul 2026 |
| 192.31.27.0/24 | 256 | RIPE NCC | FR | 14th Apr 1987 |
| 192.31.28.0/24 | 256 | ARIN | US | 22nd Apr 1987 |
| 192.31.29.0/24 | 256 | ARIN | US | 17th Jan 2025 |
| 192.31.3.0/24 | 256 | ARIN | US | 8th Apr 1993 |
| 192.31.30.0/24 | 256 | ARIN | US | 22nd Apr 1987 |
| 192.31.31.0/24 | 256 | RIPE NCC |  GB | 21st Apr 1987 |
| 192.31.37.0/24 | 256 | ARIN | US | 6th Apr 1987 |
| 192.31.38.0/24 | 256 | ARIN | US | 15th Apr 1987 |
| 192.31.39.0/24 | 256 | ARIN | US | 18th May 1988 |
| 192.31.40.0/24 | 256 | RIPE NCC |  BE | 24th Apr 1990 |
| 192.31.42.0/24 | 256 | ARIN | US | 8th Mar 1991 |
| 192.31.44.0/24 | 256 | ARIN | US | 13th Mar 1991 |