ARIN's free /24 became one trust-company /28 and 15/16 reserved

ARIN Allocated One-Sixteenth of an IPv6 Block. The Other Fifteen Went on Hold.

Why it matters

A trust company received one /28 on 2 November. In ARIN's next daily inventory, the surrounding /24 had disappeared from the available column: one slice allocated, four adjacent slices reserved. The public ledger gives the arithmetic and withholds the reason for the hold.

Theo March3 November 2026Reading Time 2 minLast update: 3 November 2026

ARIN’s daily inventory moved one /28 to a named holder and classified the adjacent fifteen /28-equivalent slices as reserved.

Summary

ARIN's 2 November extended delegated file lists 2600:2f00::/24 as one available IPv6 range. Its 3 November file replaces that row with one allocated /28 and four reserved neighbours.
ARIN's exact RDAP record names Manufacturers and Traders Trust Company as holder of the /28. The other fifteen sixteenths have no named holder in the delegated file.

A single allocation consumed one-sixteenth of a block and changed the public label on all sixteen. In the 2 November inventory, 2600:2f00::/24 is one open available row. In the next file, ARIN records 2600:2f00::/28 as allocated on 2 November. It carves the rest into 2600:2f10::/28, 2600:2f20::/27, 2600:2f40::/26 and 2600:2f80::/25, each marked reserved. The five ranges fit together exactly, with no gap or overlap. The named allocation is one of sixteen equal /28 slices; the four reserved rows cover the other fifteen.

The beneficiary is visible on the smaller piece. ARIN's network card calls it MTT-IPV6-1, records a direct allocation to Manufacturers and Traders Trust Company and dates registration to 2 November at 15:14:51 UTC. The larger administrative move is visible only by comparing the two daily files. A reader who counts allocated rows sees one new /28. A reader who counts remaining available inventory sees the whole /24 leave that category. Those are different balances on the same public ledger.

The official extended-file specification defines reserved as space neither allocated nor assigned and unavailable for further allocation or assignment for some reason. It lists possible reasons, including growth space and set-asides. Neither daily row identifies the reason for these particular four reserves.