Which company owns MAC address prefix 38:31:5A?

MAC address prefix 38:31:5A is registered to Rinnai in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 38:31:5A has a network interface built by Rinnai.

What is the OUI 38:31:5A?

38:31:5A is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Rinnai. It covers every address from 38:31:5A:00:00:00 to 38:31:5A:FF:FF:FF, or 16,777,216 addresses in total. It is also written 38-31-5A.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in 38:31:5A:00:00:00 that is 38:31:5A — 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 Rinnai located?

Rinnai is listed at 103 International Drive Peachtree City GA US 30269 in the IEEE OUI registry entry for 38:31:5A. This is the address the organization registered with the IEEE, which may differ from its current operating address.

Rinnai

MAC address prefix 38:31:5A is registered to Rinnai in the IEEE OUI registry. Any device whose MAC address begins with 38:31:5A has a network interface built by Rinnai. 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 38:31:5A:00:00:00 to 38:31:5A:FF:FF:FF.

OUI prefix: 38:31:5A
Hyphen form: 38-31-5A
MAC range: 38:31:5A:00:00:00 – 38:31:5A:FF:FF:FF
Addresses in block: 16,777,216
Organization: Rinnai
Address: 103 International Drive Peachtree City GA US 30269
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.

2023-07-11Assigned to "Rinnai"
archived source →
2026-07-17Assigned to "Rinnai"

Nearby in the registry

The prefixes assigned immediately before and after 38:31:5A:

FAQ

Which company owns MAC address prefix 38:31:5A?: MAC address prefix 38:31:5A is registered to Rinnai in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 38:31:5A has a network interface built by Rinnai.
What is the OUI 38:31:5A?: 38:31:5A is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Rinnai. It covers every address from 38:31:5A:00:00:00 to 38:31:5A:FF:FF:FF, or 16,777,216 addresses in total. It is also written 38-31-5A.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in 38:31:5A:00:00:00 that is 38:31:5A — 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 Rinnai located?: Rinnai is listed at 103 International Drive Peachtree City GA US 30269 in the IEEE OUI registry entry for 38:31:5A. This is the address the organization registered with the IEEE, which may differ from its current operating address.