How MAC Address Vendor Lookup Works

Every standard MAC address contains a vendor prefix known as an Organizationally Unique Identifier (OUI). The IEEE Registration Authority assigns these prefixes to organizations, and the assignment is published in a registry. This tool cleans up your input, detects the prefix, and searches a cached copy of the IEEE listing to find the matching vendor record.

Step-by-Step

• 1) Paste a MAC or OUI: Enter formats like 3C:5A:B4:12:34:56, 3C-5A-B4-12-34-56, or 3C5AB4.
• 2) Normalize: The tool strips separators and non-hex characters, then rebuilds a consistent view of the MAC and its first 3 bytes.
• 3) Extract the OUI: The first 6 hex characters (3 bytes) are used as the lookup key.
• 4) Search the IEEE listing: A local cache file is scanned for a matching “(base 16)” record for that prefix.
• 5) Display results: You’ll see the vendor name, the detected prefix, optional address lines when available, and the cache freshness.

Key Features

Flexible MAC Address Input

Accepts common separators (colons, hyphens, dots) and also supports entering only the vendor prefix. This is useful when you only have the first three bytes from logs or packet captures.

Clean Normalization and Validation

The tool validates that your input contains enough hexadecimal data to form a vendor prefix. It also shows the normalized form so you can quickly spot typos before trusting the result.

IEEE-Based Vendor Registry

Vendor names come from the IEEE public listing. When “refresh registry” is enabled, the tool can update its local cache from the IEEE source URL and reuse it for future lookups.

Detailed vs. Compact Output

Choose a compact result (vendor only) or a detailed report that includes the normalized MAC, extracted OUI, and any available address lines from the registry entry.

Copy and Download

One click copies the output to your clipboard, and you can also download a plain-text report for tickets, audits, or documentation.

Use Cases

• Network troubleshooting: Identify unknown devices in ARP tables, DHCP leases, or switch CAM tables.
• Security triage: Quickly check whether a suspicious MAC prefix maps to a known vendor or looks unexpected for your environment.
• Asset inventory: Enrich spreadsheets and CMDB records with manufacturer names based on observed MAC addresses.
• Packet capture analysis: Add context while reviewing PCAPs by mapping MAC sources/destinations to organizations.
• IoT and Wi‑Fi management: Spot consumer devices, AP chipsets, and embedded vendors during onboarding or segmentation work.
• Vendor verification: Confirm the prefix for a device label or documentation before deploying at scale.

Because the lookup is based on the OUI prefix, it is most effective as a quick attribution step. It does not prove the exact device model, and it cannot guarantee authenticity if a MAC address is spoofed, but it’s a fast way to add vendor context to your workflow.

Optimization Tips

Prefer the Full MAC When You Have It

If possible, paste the full 12-hex MAC address. The tool still uses the OUI prefix, but the normalized full MAC makes it easier to compare your input against logs and prevents accidental truncation.

Refresh the Registry Periodically

Organizations receive new OUI assignments over time. Enabling registry refresh ensures your cache stays current. If your server blocks outbound traffic, you can still use the cached copy until the next update.

Know the Limits of OUI Attribution

Some vendors resell chipsets or manufacture for others, and locally administered addresses may not map cleanly to a public registry entry. Use the result as a hint, then corroborate with DHCP hostnames, switch port data, or inventory records.

FAQ