MAC Address OUI Vendor Lookup
MAC Address OUI Vendor Lookup: Normalizes a MAC address and compares its first 24 bits with five bundled OUI sample prefixes; it does not query the IEEE registry.
About this mac address oui vendor lookup
MAC Address OUI Vendor Lookup — browser-based utility.
How this tool works
Implements client-side offline MAC Address OUI lookup. It normalizes 12 hexadecimal digits, extracts the first 24-bit OUI, and compares it with five bundled sample prefixes; it does not query the IEEE registry or inspect network devices.
- Protocol Message De-serialization: Parses raw DNS wire-format byte streams or HAR 1.2 JSON waterfall entries.
- Record Validation & Separation: Enforces RFC 6844 requirements that CAA authorization ('issue', 'issuewild') and reporting ('iodef') tags reside on separate records.
- Waterfall Timing Analysis: Sums network phases (blocked, dns, connect, ssl, send, wait, receive) to evaluate latency waterfalls.
- Visual Diagnostic Reporting: Renders color-coded waterfall timelines and highlights high-latency assets or missing HTTP caching headers.
Worked example
Scenario: Look up a bundled Apple OUI without querying a network.
Sample input:
Processing: Normalize twelve hexadecimal digits, use 001B63 as the OUI, and inspect the first-octet bits.
Illustrative output:
Limits and verification
Rejects combined single-line CAA records that violate RFC 6844 syntax. In HAR file analysis, protects against multi-gigabyte log allocations by parsing entry streams with memory safety bounds.
Examples demonstrate an expected workflow; they do not prove every input or every branch of an external specification. Check important results with an independent source before using them for money, security, compliance, safety, or irreversible file changes.
Browser processing boundary
Tool input is processed by code running in the browser and is not intentionally sent to a CZOA processing API. The page can still request ordinary site assets, analytics, or advertising when those services are enabled. Browser extensions and managed-device software remain outside this tool's control.
Relevant references
These references govern or help explain the format, protocol, or calculation used here. Listing a reference does not claim certification or complete implementation of every optional feature.
Content owner: CZOA Tools · Last reviewed: 2026-09-15 · Review methodology
How to use it
- Enter, paste, or select your input data into the MAC Address OUI Vendor Lookup workspace controls.
- Review available parameter fields, units, formats, or options configured for your task.
- Click the action button or observe immediate live calculations rendered in your browser runtime.
- Inspect the resulting output and any diagnostic messages, then copy or download the result if needed.
Frequently asked questions
How does the offline MAC lookup derive its result?+
It removes every non-hexadecimal character, uppercases the remaining digits, requires exactly 12 digits, and formats them as colon-separated octets. The first six digits form the OUI. It matches only five bundled prefixes: Apple, IANA, Raspberry Pi Foundation, Samsung, and Google.
What controls and output does the page provide?+
The page provides one multiline Input field, Run locally, and Load sample. The sample 00:1B:63:AA:BB:CC produces mac 00:1B:63:AA:BB:CC, oui 001B63, vendor Apple, Inc., unicast true, and locallyAdministered false. There is no file upload, interface scan, ARP capture, or network query control.
What limits apply to vendor and address classification?+
A value with anything other than 12 hexadecimal digits after separators are removed is rejected. An unlisted OUI returns Unknown in bundled sample. The low bit of the first octet decides unicast; its next bit decides locally administered. This small local table is not authoritative IEEE coverage.
What did isolated browser verification establish?+
With Input set to 00:1B:63:AA:BB:CC, Run locally normalizes the address, matches bundled OUI 001B63, and returns Apple, Inc. with unicast true and locallyAdministered false. This verifies one entry in the five-prefix bundled table; it does not query the current IEEE registry or discover devices on a network.