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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 155.35.228.0/22 | 1k | ARIN |  US | 4th Feb 1992 |
| 155.35.233.0/24 | 256 | ARIN | US | 4th Feb 1992 |
| 155.35.234.0/23 | 512 | ARIN | US | 4th Feb 1992 |
| 155.35.236.0/22 | 1k | ARIN | US | 4th Feb 1992 |
| 155.35.240.0/20 | 4.1k | ARIN | US | 4th Feb 1992 |
| 155.35.32.0/23 | 512 | ARIN | US | 4th Feb 1992 |
| 155.35.36.0/22 | 1k | ARIN | US | 4th Feb 1992 |
| 155.35.4.0/22 | 1k | ARIN | US | 4th Feb 1992 |
| 155.35.40.0/22 | 1k | ARIN | US | 4th Feb 1992 |
| 155.35.44.0/23 | 512 | ARIN | US | 4th Feb 1992 |
| 155.35.48.0/20 | 4.1k | ARIN | US | 4th Feb 1992 |
| 155.35.64.0/18 | 16.4k | ARIN | US | 4th Feb 1992 |
| 155.35.8.0/21 | 2k | ARIN | US | 4th Feb 1992 |
| 155.36.0.0/16 | 65.5k | ARIN | US | 8th Apr 1992 |
| 155.46.64.0/19 | 8.2k | ARIN | US | 26th Aug 1994 |
| 155.46.96.0/19 | 8.2k | ARIN | US | 26th Aug 1994 |
| 155.51.0.0/16 | 65.5k | ARIN | US | 23rd Mar 1992 |
| 155.61.0.0/16 | 65.5k | ARIN | US | 30th Oct 1991 |
| 155.66.0.0/16 | 65.5k | RIPE NCC |  CH | 26th Mar 1992 |
| 155.67.0.0/16 | 65.5k | ARIN | US | 31st Oct 1991 |
| 155.68.0.0/16 | 65.5k | ARIN | US | 30th Oct 1991 |
| 155.71.0.0/16 | 65.5k | APNIC |  AU | 30th Oct 1991 |
| 155.90.0.0/16 | 65.5k | ARIN | US | 31st Oct 1991 |
| 155.94.234.0/24 | 256 | ARIN | US | 11th Jun 2014 |
| 155.94.80.0/20 | 4.1k | ARIN | US | 13th Oct 2022 |
| 155.96.0.0/16 | 65.5k | ARIN | US | 13th Nov 1991 |
| 156.0.204.0/22 | 1k | AFRINIC |  CI | 28th Feb 2020 |
| 156.0.252.0/24 | 256 | AFRINIC |  ZA | 7th Aug 2017 |
| 156.0.253.0/24 | 256 | AFRINIC | ZA | 13th Oct 2017 |
| 156.0.64.0/21 | 2k | AFRINIC | ZA | 27th Oct 2017 |
| 156.100.0.0/16 | 65.5k | ARIN | US | 24th Dec 1991 |
| 156.102.0.0/16 | 65.5k | ARIN | US | 24th Dec 1991 |
| 156.103.0.0/16 | 65.5k | ARIN | US | 24th Dec 1991 |
| 156.104.0.0/16 | 65.5k | ARIN | US | 24th Dec 1991 |
| 156.105.0.0/16 | 65.5k | ARIN | US | 24th Dec 1991 |
| 156.117.0.0/16 | 65.5k | ARIN | US | 8th Jan 1992 |
| 156.119.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.120.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.121.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.122.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.123.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.124.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.125.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.126.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.127.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.128.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.129.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.130.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.131.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.132.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |