rirtracker

IPv4 range · 16,777,216 addresses

51.0.0.0/8

Now

ARIN statistics
Allocated (dated 2019-01-10), allocated (dated 2019-03-11), allocated (dated 2019-09-03), allocated (dated 2020-03-31) (CA, US), in the latest file
Registry
Not known
Holder
Not looked up

Latest change

Not in ARIN-Issued Removed (return, revocation or reclamation not publicly distinguishable)

Reported
2009-02-26 (ARIN)
Confidence
Strong inference
Inventory
Possible future reissue candidate after hold

Hold

Removed
2009-02-26 (ARIN)
Estimated hold end
2009-04-27 (from ARIN's published rule)
Now
Possible reissue candidate; not confirmed available.

Timeline (1)

Every change the tracker has found, newest first. It covers ARIN from 2008-12-01, the RIPE NCC from 2010-04-23, APNIC from 2008-02-15, LACNIC from 2012-06-29 and AFRINIC from 2012-10-03.

2009-02-26 ARIN Not in ARIN-Issued Removed (return, revocation or reclamation not publicly distinguishable) Strong inference
Inventory
Possible future reissue candidate after hold
Hold estimate
Estimated hold end 2009-04-27. Possible reissue candidate after this date; not confirmed available.

Removed from active registration. ARIN-Issued didn't list this; the tracker found it by comparing ARIN's daily statistics. ARIN's statistics show it assigned (dated 1991-09-16) on 2009-02-25 and not issued on 2009-02-27. (Until 2013-03-05, ARIN's statistics list only what's issued.) Public sources do not distinguish a voluntary return, revocation, or reclamation. ARIN holds returned, revoked and reclaimed IPv4 space for 60 days before reissuing it, so the estimated hold end is 2009-04-27. This does not confirm availability.

Evidence (3) · classifier 1.4.0,
  1. Statistics Not listed in ARIN-Issued; found by comparing ARIN's daily statistics: 51.0.0.0/8 assigned on 2009-02-26, not listed on 2009-02-27 source · retrieved
  2. Before ARIN delegated statistics 2009-02-25, before the report: assigned (dated 1991-09-16) source · retrieved
  3. After ARIN delegated statistics 2009-02-27, after the report: not issued source · retrieved
Classification history for this change (4 versions)
  1. : Removed (return, revocation or reclamation not publicly distinguishable), strong inference (classifier 1.3.0)
  2. : Removed (return, revocation or reclamation not publicly distinguishable), strong inference (classifier 1.3.1)
  3. : Removed (return, revocation or reclamation not publicly distinguishable), strong inference (classifier 1.3.2)
  4. : Removed (return, revocation or reclamation not publicly distinguishable), strong inference (classifier 1.4.0) current

Changes to overlapping ranges

DateRegistryRangeRecorded asWhat happened
2025-11-11RIPE NCC51.0.0.0/19Transfer logIntra-RIPE NCC transfer
2025-11-11RIPE NCC51.0.128.0/17Transfer logIntra-RIPE NCC transfer
2025-11-11RIPE NCC51.72.0.0/15Transfer logIntra-RIPE NCC transfer
2025-05-14RIPE NCC51.179.0.0/17Transfer logIntra-RIPE NCC transfer
2020-03-31ARIN51.222.0.0/16+ AddTransfer into ARIN
2020-03-31RIPE NCC51.222.0.0/16Transfer logTransfer out of the RIPE NCC
2019-11-14RIPE NCC51.162.0.0/17Transfer logTransfer out of the RIPE NCC
2019-11-14APNIC51.162.0.0/17Transfer logTransfer into APNIC
2019-09-03ARIN51.161.0.0/16+ AddTransfer into ARIN
2019-09-03RIPE NCC51.161.0.0/16Transfer logTransfer out of the RIPE NCC
2019-03-11ARIN51.81.0.0/16+ AddTransfer into ARIN
2019-03-11RIPE NCC51.81.0.0/16Transfer logTransfer out of the RIPE NCC
2019-01-10ARIN51.79.0.0/16+ AddTransfer into ARIN
2019-01-10RIPE NCC51.79.0.0/16Transfer logTransfer out of the RIPE NCC
2015-05-29RIPE NCC51.211.0.0/16Transfer logIntra-RIPE NCC transfer
2015-05-29RIPE NCC51.218.0.0/16Transfer logIntra-RIPE NCC transfer
2015-05-29RIPE NCC51.223.0.0/16Transfer logIntra-RIPE NCC transfer
2015-05-29RIPE NCC51.235.0.0/16Transfer logIntra-RIPE NCC transfer
2015-05-29RIPE NCC51.252.0.0/15Transfer logIntra-RIPE NCC transfer

Transfer records (18)

Date (UTC)LogTypeRange movedFromTo
RIPE NCCResource transfer51.0.0.0/19 A100 ROW Inc RIPE NCCAmazon Data Services European Sovereign Cloud GmbH RIPE NCC
RIPE NCCResource transfer51.72.0.0/15 A100 ROW Inc RIPE NCCAmazon Data Services European Sovereign Cloud GmbH RIPE NCC
RIPE NCCResource transfer51.179.0.0/17 SHELLNET S.P.A. RIPE NCCOpnet Srl RIPE NCC
RIPE NCCResource transfer51.222.0.0/16 OVH SAS RIPE NCC(no name given) ARIN
ARINResource transfer51.222.0.0/16 OVH SAS RIPE NCCOVH Hosting, Inc. ARIN
RIPE NCCResource transfer51.162.0.0/17 Equinix Services Limited RIPE NCC(no name given) APNIC
APNICResource transfer51.162.0.0/17 ORG-IA69-RIPE RIPE NCCEQUINIX (AUSTRALIA) ENTERPRISES PTY LIMITED APNIC
RIPE NCCResource transfer51.161.0.0/16 OVH SAS RIPE NCC(no name given) ARIN
ARINResource transfer51.161.0.0/16 OVH SAS RIPE NCCOVH Hosting, Inc. ARIN
RIPE NCCResource transfer51.81.0.0/16 OVH SAS RIPE NCC(no name given) ARIN
ARINResource transfer51.81.0.0/16 OVH SAS RIPE NCCOVH US LLC ARIN
RIPE NCCResource transfer51.79.0.0/16 OVH SAS RIPE NCC(no name given) ARIN
ARINResource transfer51.79.0.0/16 OVH SAS RIPE NCCOVH Hosting, Inc. ARIN
RIPE NCCResource transfer51.211.0.0/16 S.C. GVM SISTEM 2003 S.R.L. RIPE NCCSaudi Telecom Company JSC RIPE NCC
RIPE NCCResource transfer51.218.0.0/16 S.C. GVM SISTEM 2003 S.R.L. RIPE NCCSaudi Telecom Company JSC RIPE NCC
RIPE NCCResource transfer51.223.0.0/16 S.C. GVM SISTEM 2003 S.R.L. RIPE NCCSaudi Telecom Company JSC RIPE NCC
RIPE NCCResource transfer51.235.0.0/16 S.C. GVM SISTEM 2003 S.R.L. RIPE NCCSaudi Telecom Company JSC RIPE NCC
RIPE NCCResource transfer51.252.0.0/15 S.C. GVM SISTEM 2003 S.R.L. RIPE NCCSaudi Telecom Company JSC RIPE NCC

Every record in the ARIN, RIPE NCC, APNIC, LACNIC and AFRINIC transfer logs that moved any part of this IPv4 range (ARIN's from 2009, the RIPE NCC's from 2012, APNIC's from 2010, LACNIC's from 2016, AFRINIC's from 2018). A transfer between two registries is in both logs.

RDAP lookups

Not looked up. The tracker queries RDAP for changes as they're reported (on first sight, after 24 hours and after seven days); older changes aren't looked up because today's RDAP says nothing about the past.

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