NAKAYO Inc. — 6 prefixes (MA-L)

A MAC address beginning with one of six IEEE-registered prefixes (00:D0:EC, 48:0C:49, 8C:3C:4A, B0:4B:68, C8:07:39, F4:96:51) belongs to NAKAYO Inc, a Japanese business-telephone and PBX equipment manufacturer, and is most likely seen on office VoIP handsets, PBX line/network cards, or business routers rather than consumer devices.

NAKAYO (株式会社ナカヨ) is a longstanding Maebashi, Gunma-based manufacturer — third-party company profiles put it at roughly 729 employees and about $162.97M in revenue, making business-phone and PBX systems with customers including NTT. Holding six separate OUI blocks across two registered addresses is itself corroborating evidence of an active, recurring registrant rather than a shell registration.

All six blocks are MA-L (/24) assignments; no MA-M or MA-S registrations exist for NAKAYO in the cached registries. Two physical addresses alternate across the six: "1-3-2, Soja-machi, Maebashi-shi, Gunma" covers F4:96:51, B0:4B:68, and C8:07:39, while "Development Support Center, 165 Higashiomuro-machi, Maebashi-shi, Gunma" covers 00:D0:EC, 48:0C:49, and 8C:3C:4A. The Wireshark the Wireshark manufacturer database file independently confirms all six prefixes as NAKAYO.

IEEE's public OUI data does not publish assignment or registration dates for any of these blocks. One third-party aggregator (maclookup.app) lists an October 3, 2016 "registered" date for F4:96:51 — this is that aggregator's own database artifact, not an IEEE fact, and is not treated as a registration date here.

No Nakayo-specific CVEs or vendor security advisories turned up in a targeted search. That is a sourced absence of findings, not a claim that the vendor's products are free of security issues.