Which company owns MAC address prefix EC:74:D7?

MAC address prefix EC:74:D7 is registered to Grandstream Networks Inc in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with EC:74:D7 has a network interface built by Grandstream Networks Inc.

What is the OUI EC:74:D7?

EC:74:D7 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Grandstream Networks Inc. It covers every address from EC:74:D7:00:00:00 to EC:74:D7:FF:FF:FF, or 16,777,216 addresses in total. It is also written EC-74-D7.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in EC:74:D7:00:00:00 that is EC:74:D7 — and look that prefix up in the IEEE OUI registry. If the second-lowest bit of the first octet is set, the address is locally administered (a randomized or private MAC), which belongs to no manufacturer and will not resolve; modern phones and laptops use these by default on each network.

Where is Grandstream Networks Inc located?

Grandstream Networks Inc is listed at 126 brookline avenue boston MA US 02215 in the IEEE OUI registry entry for EC:74:D7. This is the address the organization registered with the IEEE, which may differ from its current operating address.

Grandstream Networks Inc

MAC address prefix EC:74:D7 is registered to Grandstream Networks Inc in the IEEE OUI registry. Any device whose MAC address begins with EC:74:D7 has a network interface built by Grandstream Networks Inc. This prefix (the OUI, or Organizationally Unique Identifier) is assigned by the IEEE and is the first three octets of the address — it covers every MAC from EC:74:D7:00:00:00 to EC:74:D7:FF:FF:FF.

OUI prefix: EC:74:D7
Hyphen form: EC-74-D7
MAC range: EC:74:D7:00:00:00 – EC:74:D7:FF:FF:FF
Addresses in block: 16,777,216
Organization: Grandstream Networks Inc
Address: 126 brookline avenue boston MA US 02215
Source: IEEE OUI registry

Have a full MAC address? Look it up— we'll also tell you if it's a randomized (private) address rather than a real manufacturer prefix.

Assignment history (2)

The IEEE registry publishes current state only — this is the change record we've kept since we started tracking it daily.

2022-07-11Assigned to "Grandstream Networks Inc"
archived source →
2026-07-17Assigned to "Grandstream Networks Inc"

Nearby in the registry

The prefixes assigned immediately before and after EC:74:D7:

FAQ

Which company owns MAC address prefix EC:74:D7?: MAC address prefix EC:74:D7 is registered to Grandstream Networks Inc in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with EC:74:D7 has a network interface built by Grandstream Networks Inc.
What is the OUI EC:74:D7?: EC:74:D7 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Grandstream Networks Inc. It covers every address from EC:74:D7:00:00:00 to EC:74:D7:FF:FF:FF, or 16,777,216 addresses in total. It is also written EC-74-D7.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in EC:74:D7:00:00:00 that is EC:74:D7 — and look that prefix up in the IEEE OUI registry. If the second-lowest bit of the first octet is set, the address is locally administered (a randomized or private MAC), which belongs to no manufacturer and will not resolve; modern phones and laptops use these by default on each network.
Where is Grandstream Networks Inc located?: Grandstream Networks Inc is listed at 126 brookline avenue boston MA US 02215 in the IEEE OUI registry entry for EC:74:D7. This is the address the organization registered with the IEEE, which may differ from its current operating address.