MAC OUI (Organizationally Unique Identifier) Regex for JavaScript
/^[0-9a-fA-F]{2}(?::[0-9a-fA-F]{2}){2}$/What this pattern does
This page provides a well-structured, multi-part regular expression for matching mac oui (organizationally unique identifier), ported and verified for JavaScript. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your JavaScript project — whether you're validating in an Express middleware, a Next.js API route, or a client-side form.
Javascript Implementation
// MAC OUI (Organizationally Unique Identifier)
// ReDoS-safe | RegexVault — Web & Network > MAC Address
const macOuiOrganizationallyUniqueIdentifierRegex = /^[0-9a-fA-F]{2}(?::[0-9a-fA-F]{2}){2}$/;
function validateMacOuiOrganizationallyUniqueIdentifier(input: string): boolean {
return macOuiOrganizationallyUniqueIdentifierRegex.test(input);
}
// Example
console.log(validateMacOuiOrganizationallyUniqueIdentifier("00:1a:2b")); // trueTest Cases
Matches (Valid) | Rejects (Invalid) |
|---|---|
00:1a:2b | 00:1a |
FF:FF:FF | 00:1a:2b:3c |
A0:B1:C2 | 00:1a:2b:3c:4d:5e |
00:50:56 | GG:HH:II |
DC:A6:32 | 001a2b |
When to use this pattern
This pattern is drawn from the Web & Network > MAC Address category and carries a ReDoS-safe certification. That matters for JavaScript developers because especially critical in long-running Node.js event loops where a ReDoS vulnerability can block the entire process. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.
Common Pitfalls
Locally administered bits (bit 1 of the first byte) indicate the MAC was not assigned by a manufacturer — check the second-least-significant bit of the first octet.
Technical Notes
00:50:56 is VMware, DC:A6:32 is Raspberry Pi Foundation. OUI lookup databases (IEEE public registry) can identify vendors from this prefix.
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