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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 States
26,993 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 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 |
| 155.14.0.0/16 | 65.5k | ARIN | US | 30th Oct 1991 |
| 155.142.0.0/16 | 65.5k | ARIN | US | 13th Nov 1991 |
| 155.157.0.0/16 | 65.5k | ARIN | US | 14th Nov 1991 |
| 155.16.0.0/16 | 65.5k | ARIN | US | 30th Oct 1991 |
| 155.162.0.0/16 | 65.5k | ARIN | US | 24th Mar 1992 |
| 155.164.0.0/16 | 65.5k | ARIN | US | 24th Mar 1992 |
| 155.167.0.0/16 | 65.5k | ARIN | US | 24th Mar 1992 |
| 155.168.0.0/16 | 65.5k | ARIN | US | 24th Mar 1992 |
| 155.169.0.0/16 | 65.5k | ARIN | US | 24th Mar 1992 |
| 155.17.0.0/16 | 65.5k | ARIN | US | 30th Oct 1991 |
| 155.171.0.0/16 | 65.5k | ARIN | US | 24th Mar 1992 |
| 155.172.0.0/16 | 65.5k | ARIN | US | 24th Mar 1992 |
| 155.173.0.0/16 | 65.5k | ARIN | US | 24th Mar 1992 |
| 155.174.0.0/16 | 65.5k | ARIN | US | 24th Mar 1992 |
| 155.175.0.0/16 | 65.5k | ARIN | US | 24th Mar 1992 |
| 155.176.0.0/16 | 65.5k | ARIN | US | 24th Mar 1992 |
| 155.177.0.0/16 | 65.5k | ARIN | US | 15th Nov 1991 |
| 155.179.0.0/16 | 65.5k | ARIN | US | 23rd Mar 1992 |
| 155.180.0.0/16 | 65.5k | ARIN | US | 18th Nov 1991 |
| 155.182.0.0/16 | 65.5k | ARIN | US | 18th Nov 1991 |
| 155.189.0.0/16 | 65.5k | ARIN | US | 4th Oct 1993 |
| 155.191.0.0/16 | 65.5k | ARIN | US | 22nd Nov 1991 |
| 155.195.0.0/16 | 65.5k | ARIN | US | 22nd Nov 1991 |
| 155.200.0.0/16 | 65.5k | ARIN | US | 30th Oct 1991 |
| 155.208.0.0/16 | 65.5k | ARIN | US | 19th Aug 1996 |
| 155.224.0.0/16 | 65.5k | ARIN | US | 14th Feb 1992 |
| 155.241.0.0/16 | 65.5k | ARIN | US | 9th Dec 1991 |
| 155.242.0.0/16 | 65.5k | ARIN | US | 9th Dec 1991 |
| 155.243.0.0/16 | 65.5k | ARIN | US | 9th Dec 1991 |
| 155.244.0.0/16 | 65.5k | ARIN | US | 11th Dec 1991 |
| 155.254.1.0/24 | 256 | ARIN | US | 11th Dec 1991 |
| 155.254.128.0/23 | 512 | ARIN | US | 11th Dec 1991 |
| 155.254.130.0/24 | 256 | ARIN | US | 11th Dec 1991 |
| 155.254.131.0/24 | 256 | ARIN | US | 11th Sept 2015 |
| 155.254.216.0/22 | 1k | ARIN | US | 8th Jan 2021 |
| 155.254.232.0/22 | 1k | ARIN | US | 11th Jan 2021 |
| 155.34.0.0/16 | 65.5k | ARIN | US | 23rd Mar 1992 |
| 155.35.0.0/24 | 256 | ARIN | US | 4th Feb 1992 |
| 155.35.128.0/18 | 16.4k | ARIN | US | 4th Feb 1992 |