Posted: Friday, 12 December 2025
ARIN
Executive Summary
On 2 December 2025, an IPv4 block 23.150.164.0/24, correctly allocated to the Original Customer, was inadvertently removed and reissued to the Requesting Customer during a 4.10 allocation process. This error stemmed from the current manual and partially offline 4.10 inventory process.
The incorrect state persisted until 9 December 2025, when the Original Customer reported the issue. ARIN restored the 23.150.164.0/24 to the Original Customer, issued a replacement /24 to the Requesting Customer, coordinated withdrawal of the incorrect route announcement, and notified the affected parties.
This incident highlights known weaknesses in ARIN’s current Internet Number Resources (INR) Inventory handling for 4.10 transition space and underscores the need to complete the transition to a fully automated, integrated online inventory architecture.
Incident Description
Following the current allocation process for 4.10 space, an RSD analyst:
Relied on legacy/manual 4.10 inventory artifacts, including a flat file and sparse allocation spreadsheet
Did not recognize indicators in ARIN Online showing that 23.150.164.0/24 was already allocated to the Original Customer
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