MA-M: a /28 block, one IEEE assigns within a larger OUI when a full /24 isn't needed, covering 1,048,576 addresses.
Prefix20:B3:7F:C0:00:00 /28
Vendor addressGrafenbergerstraße 37 Eggenburg AT 3730
Country🇦🇹 Austria
RegisteredMar 12, 2026
Block range20:B3:7F:C0:00:00– 20:B3:7F:CF:FF:FF
Address capacity1,048,576
AdministrationUniversally administered: its prefix comes from a block registered through the IEEE Registration Authority
TransmissionUnicast: addressed to a single device
SourceIEEE Registration Authority
Address capacity is the size of this registered block, not a count of devices actually manufactured or online. Registration identifies the organization holding the block, not a specific device model or unit.
Curious how a prefix like this turns into a full address? See how MAC addresses are structured →
Example addresses in this block
Where this block sits
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20:B3:7F:B0:00:00 /28
Shenzhen Hengbang Xinchuang Technology Co.,Ltd
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20:B3:7F:D0:00:00 /28
Xunmu Information Technology (Shanghai) Co., Ltd.
The nearest registered blocks of the same size on either side of this one in IEEE's address space.
EGSTON Power Electronics GmbH holds 1 registered blocks in the IEEE registry, ranking #11,302 of 33,421 organizations by block count.