Which company owns MAC address prefix 04:9F:81?

MAC address prefix 04:9F:81 is registered to NETSCOUT SYSTEMS INC in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 04:9F:81 has a network interface built by NETSCOUT SYSTEMS INC.

What is the OUI 04:9F:81?

04:9F:81 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to NETSCOUT SYSTEMS INC. It covers every address from 04:9F:81:00:00:00 to 04:9F:81:FF:FF:FF, or 16,777,216 addresses in total. It is also written 04-9F-81.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in 04:9F:81:00:00:00 that is 04:9F:81 — 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 NETSCOUT SYSTEMS INC located?

NETSCOUT SYSTEMS INC is listed at 310 Littleton Road Westford MA US 01886 in the IEEE OUI registry entry for 04:9F:81. This is the address the organization registered with the IEEE, which may differ from its current operating address.

How many MAC prefixes does NETSCOUT SYSTEMS INC own?

NETSCOUT SYSTEMS INC holds 4 OUI prefixes in the IEEE registry, of which 04:9F:81 is one. A device made by NETSCOUT SYSTEMS INC could carry a MAC address from any of them.

NETSCOUT SYSTEMS INC

MAC address prefix 04:9F:81 is registered to NETSCOUT SYSTEMS INC in the IEEE OUI registry. Any device whose MAC address begins with 04:9F:81 has a network interface built by NETSCOUT SYSTEMS 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 04:9F:81:00:00:00 to 04:9F:81:FF:FF:FF.

OUI prefix: 04:9F:81
Hyphen form: 04-9F-81
MAC range: 04:9F:81:00:00:00 – 04:9F:81:FF:FF:FF
Addresses in block: 16,777,216
Organization: NETSCOUT SYSTEMS INC
Address: 310 Littleton Road Westford MA US 01886
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.

Other prefixes from NETSCOUT SYSTEMS INC

NETSCOUT SYSTEMS INC holds 4 OUI prefixes in total. A device with this exact prefix could just as well carry any of these:

Assignment history (4)

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

2016-07-29Assigned to "NetScout Systems, Inc."
archived source →
2019-07-04Renamed from "NetScout Systems, Inc." to "NetAlly"
archived source →
2021-02-25Renamed from "NetAlly" to "NETSCOUT SYSTEMS INC"
archived source →
2026-07-17Assigned to "NETSCOUT SYSTEMS INC"

Nearby in the registry

The prefixes assigned immediately before and after 04:9F:81:

FAQ

Which company owns MAC address prefix 04:9F:81?: MAC address prefix 04:9F:81 is registered to NETSCOUT SYSTEMS INC in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 04:9F:81 has a network interface built by NETSCOUT SYSTEMS INC.
What is the OUI 04:9F:81?: 04:9F:81 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to NETSCOUT SYSTEMS INC. It covers every address from 04:9F:81:00:00:00 to 04:9F:81:FF:FF:FF, or 16,777,216 addresses in total. It is also written 04-9F-81.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in 04:9F:81:00:00:00 that is 04:9F:81 — 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 NETSCOUT SYSTEMS INC located?: NETSCOUT SYSTEMS INC is listed at 310 Littleton Road Westford MA US 01886 in the IEEE OUI registry entry for 04:9F:81. This is the address the organization registered with the IEEE, which may differ from its current operating address.
How many MAC prefixes does NETSCOUT SYSTEMS INC own?: NETSCOUT SYSTEMS INC holds 4 OUI prefixes in the IEEE registry, of which 04:9F:81 is one. A device made by NETSCOUT SYSTEMS INC could carry a MAC address from any of them.