IBM Corp / IBM — 33 prefixes (29 MA-L, 3 MA-M, 1 MA-S)

International Business Machines holds one of the larger enterprise OUI footprints in the IEEE registry, split across three block sizes and two principal registrant names: "IBM Corp" carries the older, larger cohort of MA-L (24-bit) blocks, while "IBM" carries a newer mix that includes the MA-M (28-bit) allocations. Cached IEEE registry CSVs confirm 29 MA-L assignments, 3 MA-M assignments, and a single MA-S (36-bit) block — 70:B3:D5:70:8 — registered to the sub-entity "IBM Research GmbH" at the Zurich research lab in Rüschlikon, Switzerland. Most MA-L blocks resolve to IBM's longtime registry address at 3039 E Cornwallis Road, Research Triangle Park, North Carolina, with corporate headquarters at New Orchard Road, Armonk, New York. One legacy MA-L block, 00:10:D9, is registered to "IBM JAPAN, FUJISAWA MT+D" in Fujisawa, Kanagawa. What makes an IBM OUI distinctive on a network is that it is exclusively enterprise-grade: IBM ships no consumer or SOHO hardware. The PC division went to Lenovo in 2005 and the x86 System x server line followed in 2014, so a modern IBM MAC almost always belongs to genuine data-center infrastructure — a Z-series mainframe, a POWER-based server running AIX/IBM i/Linux, a BladeCenter or Flex System blade, or a FlashSystem/Storwize storage array. The common dual-MAC pattern on blades and rack servers (a host NIC plus a separate BMC/management interface) means an IBM host frequently presents two adjacent IBM addresses; the management interface should be isolated to a dedicated VLAN. Legacy pre-2014 System x hardware still carries IBM OUIs but is now Lenovo-serviced.

IEEE assignment

33 confirmed prefixes — 29 MA-L, 3 MA-M, 1 MA-S — registered to "IBM Corp" / "IBM" (and "IBM Research GmbH" for the MA-S block) [Confirmed] — IEEE MA-L/MA-M/MA-S (cached the IEEE MA-L registry, the IEEE MA-M registry, the IEEE MA-S registry)

Registry / block sizes

MA-L (24-bit), MA-M (28-bit), MA-S (36-bit). NOTE: IEEE's public OUI data publishes NO assignment/registration date (columns are only Registry, Assignment, Organization Name, Organization Address); any "date registered" on third-party tools (e.g. maclookup.app showing "22 April 1998" for IBM Corp or "07 October 2011" for IBM) is a database artifact, not an IEEE fact.

[Confirmed] — IEEE registry CSVs; maclookup.app

HQ / country

New Orchard Road, Armonk, NY 10504, US (corporate HQ). Primary IEEE registry address: 3039 E Cornwallis Road, Research Triangle Park, NC 27709-2195, US. [Confirmed] — IEEE registry; en.wikipedia.org/wiki/IBM

Company status

active; NYSE: IBM; founded 1911 [Confirmed] — en.wikipedia.org/wiki/IBM

Device types

IBM Z mainframes; IBM Power Systems (POWER ISA, AIX/IBM i/Linux); BladeCenter and Flex System chassis/blades; FlashSystem and Storwize storage; LinuxONE; quantum hardware. No consumer devices — PC line sold to Lenovo (2005), x86 System x sold to Lenovo (2014).

[Confirmed] — en.wikipedia.org/wiki/IBM; ibm.com support pages

Notable products

IBM Z (z16/z17) mainframes; Power10 servers; BladeCenter / Flex System; FlashSystem; Storwize; LinuxONE; IBM Quantum hardware [Confirmed] — en.wikipedia.org/wiki/IBM; techtarget.com

Verified MA-L sample prefixes (IBM Corp / IBM)

00:02:55, 00:04:AC, 00:09:6B, 00:0D:60, 08:00:5A, 00:50:76, 00:60:94, 40:F2:E9, FC:CF:62 [Confirmed] — IEEE MA-L (cached copy)

MA-M assignments (28-bit)

2C:69:1D:8, C4:FF:84:8, 90:4E:91:7 [Confirmed] — IEEE MA-M (cached copy)

MA-S assignment (36-bit)

70:B3:D5:70:8 → "IBM Research GmbH", Säumerstrasse 4, Rüschlikon ZH, CH 8803, Switzerland [Confirmed] — IEEE MA-S (cached copy)

Legacy / regional block

00:10:D9 → "IBM JAPAN, FUJISAWA MT+D", Kirihara-cho 1, Fujisawa City, Kanagawa 252, Japan [Confirmed] — IEEE MA-L (cached copy)

Related vendors

Lenovo (acquired IBM PC division 2005, x86 server division 2014 — legacy IBM System x hardware still carries IBM OUIs; current Lenovo servers carry Lenovo OUIs); IBM Research GmbH (MA-S sub-registrant 70:B3:D5:70:8) [Confirmed] — en.wikipedia.org/wiki/IBM; netify.ai

Special note

dual-MAC pattern on IBM blades/rack servers (host NIC + BMC/management interface) is well documented; isolate the management MAC to a dedicated VLAN. [Confirmed] — ibm.com BladeCenter/AMM support pages

Analyst note

An IBM OUI is exclusively enterprise — mainframe, Power server, BladeCenter/Flex blade, or storage array. IBM seen on a non-data-center segment (user LAN, guest VLAN) warrants investigation. No consumer hardware carries IBM OUIs.