LLMNR

LLMNR is a local name resolution protocol that can introduce security risks if abused.

Updated: 2026-03-05

Definition

Link-Local Multicast Name Resolution (LLMNR) resolves hostnames on a local network when DNS fails.

It can be abused by attackers for credential interception in some environments.

Key points

Fallback name resolution on local link
Can increase attack surface
Often disabled in hardened enterprise networks

Common mistakes

Leaving LLMNR enabled without understanding risk.
No DNS reliability causing frequent fallback behavior.

Related exams

CompTIA Security+ (SY0-701)

Free Security+ SY0-701 mini test. Continue in the app for offline packs and detailed explanations.

CompTIA A+ (220-1201 / 220-1202)

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