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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,001 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 155.103.12.0/22 | 1k | ARIN |  US | 2nd Apr 2026 |
| 155.103.126.0/23 | 512 | ARIN | US | 13th Jan 2026 |
| 155.103.136.0/22 | 1k | ARIN | US | 13th Jan 2026 |
| 155.103.148.0/22 | 1k | ARIN |  CA | 13th Jan 2026 |
| 155.103.16.0/22 | 1k | ARIN | US | 2nd Apr 2026 |
| 155.103.164.0/22 | 1k | ARIN | CA | 13th Jan 2026 |
| 155.103.176.0/22 | 1k | ARIN | US | 13th Jan 2026 |
| 155.103.180.0/24 | 256 | ARIN | US | 13th Jan 2026 |
| 155.103.185.0/24 | 256 | ARIN | US | 13th Jan 2026 |
| 155.103.186.0/24 | 256 | ARIN | US | 13th Jan 2026 |
| 155.103.191.0/24 | 256 | ARIN | US | 13th Jan 2026 |
| 155.103.192.0/24 | 256 | ARIN | CA | 13th Jan 2026 |
| 155.103.193.0/24 | 256 | ARIN | US | 13th Jan 2026 |
| 155.103.208.0/23 | 512 | ARIN | US | 13th Jan 2026 |
| 155.103.212.0/24 | 256 | ARIN | US | 2nd Feb 2026 |
| 155.103.213.0/24 | 256 | ARIN | US | 13th Jan 2026 |
| 155.103.220.0/24 | 256 | ARIN | US | 13th Jan 2026 |
| 155.103.221.0/24 | 256 | ARIN | US | 13th Jan 2026 |
| 155.103.222.0/24 | 256 | ARIN | US | 20th Jan 2026 |
| 155.103.228.0/22 | 1k | ARIN | US | 13th Jan 2026 |
| 155.103.232.0/22 | 1k | ARIN | US | 13th Jan 2026 |
| 155.103.24.0/22 | 1k | ARIN | US | 2nd Apr 2026 |
| 155.103.240.0/22 | 1k | ARIN | US | 2nd Apr 2026 |
| 155.103.249.0/24 | 256 | ARIN | US | 13th Jan 2026 |
| 155.103.28.0/22 | 1k | ARIN | US | 2nd Apr 2026 |
| 155.103.32.0/22 | 1k | ARIN | US | 2nd Apr 2026 |
| 155.103.36.0/22 | 1k | ARIN | CA | 2nd Apr 2026 |
| 155.103.44.0/23 | 512 | ARIN | US | 2nd Apr 2026 |
| 155.103.47.0/24 | 256 | ARIN | US | 2nd Apr 2026 |
| 155.103.52.0/22 | 1k | ARIN | US | 6th Apr 2026 |
| 155.103.60.0/23 | 512 | ARIN | US | 2nd Apr 2026 |
| 155.103.62.0/23 | 512 | ARIN | US | 2nd Apr 2026 |
| 155.103.72.0/22 | 1k | ARIN | US | 13th Jan 2026 |
| 155.103.76.0/24 | 256 | ARIN | US | 13th Jan 2026 |
| 155.103.79.0/24 | 256 | ARIN | US | 2nd Apr 2026 |
| 155.103.88.0/22 | 1k | ARIN | US | 13th Jan 2026 |
| 155.103.95.0/24 | 256 | ARIN | US | 13th Jan 2026 |
| 155.108.0.0/16 | 65.5k | ARIN | US | 5th Nov 1991 |
| 155.115.0.0/16 | 65.5k | RIPE NCC |  NL | 23rd Mar 1992 |
| 155.133.196.0/22 | 1k | RIPE NCC |  DE | 7th Nov 1991 |
| 155.137.128.0/17 | 32.8k | APNIC |  HK | 12th Nov 1991 |
| 155.137.16.0/22 | 1k | RIPE NCC |  ES | 12th Nov 1991 |
| 155.137.8.0/21 | 2k | RIPE NCC | ES | 12th Nov 1991 |
| 155.14.0.0/16 | 65.5k | ARIN | US | 30th Oct 1991 |
| 155.142.0.0/16 | 65.5k | ARIN | US | 13th Nov 1991 |
| 155.15.0.0/16 | 65.5k | ARIN | CA | 30th Oct 1991 |
| 155.157.0.0/16 | 65.5k | ARIN | US | 14th Nov 1991 |
| 155.159.0.0/16 | 65.5k | AFRINIC |  ZA | 22nd May 1992 |
| 155.16.0.0/16 | 65.5k | ARIN | US | 30th Oct 1991 |
| 155.160.0.0/16 | 65.5k | APNIC |  JP | 14th Sept 1993 |