AuthHound

Event 6274 · NPS discarded the request

NPS Event 6274 'discarded the request' — not a reject

The event text: “Network Policy Server discarded the request for a user.”

What it actually means: NPS didn’t say no — it said nothing. A 6273 (denied) means the request was evaluated and rejected: the NAS gets an Access-Reject, the client fails fast. A 6274 (discarded) means NPS threw the packet away without answering at all: the NAS sees a timeout, retries, and may fail over to a secondary RADIUS server. If users report “Wi-Fi takes forever and then fails” rather than failing instantly, you’re in discard territory.

The discard reasons cluster into three families:

1. The packet couldn’t be trusted

The most common discard: the message failed verification, so answering would be unsafe. The Reason Code / Reason line in the 6274 event says the message was malformed or its signature/authenticator couldn’t be verified. This is almost always the shared secret disagreeing between the NAS and the NPS RADIUS Client entry — the discard-flavored sibling of Reason Code 262.

Check: re-enter the shared secret on both sides; confirm the request is matching the RADIUS Client entry you think it is (source IP in the event vs. your entries).

2. The packet was malformed or unsupported

Vendor quirks: NAS firmware sending malformed attributes, unsupported RADIUS extensions, or (rarely) genuinely corrupted UDP. If the secrets check out, capture a failing exchange and compare it with a working NAS of the same model — firmware upgrades on the NAS fix a surprising share of these.

3. Server-side trouble answering at all

If discards appear for all clients at once, look at the NPS server rather than the packets:

  • NPS not registered in AD — it can’t read dial-in properties, so requests can’t be processed. Fix: right-click NPS (top node in the console) → Register server in Active Directory (adds the server to the RAS and IAS Servers group).
  • Accounting failure discards — if NPS is configured to log accounting to a SQL server or a full disk and “discard connection requests if logging fails” is enabled, an accounting outage silently discards authentications. Check Accounting configuration and the free space/SQL connectivity.
  • Event log neighbors (event 13, 4402 in the System/NPS logs) often name the server-side cause precisely.

Triage in one line

One NAS discarding → shared secret or that NAS’s firmware. Everything discarding → NPS registration or accounting/logging backend. Instant failures instead of slow ones → you’re actually looking at 6273, different playbook.

Need the NPS client registration this error is asking for? Generate it — runs in your browser →

Stop guessing which hop has the wrong secret: the open-source authhound-probe cryptographically verifies the shared secret with one test request — a pass proves the secret matches — and reports whether replies carry Message-Authenticator (the BlastRADIUS fix) while it’s at it.

export AUTHHOUND_RADIUS_SECRET='shared-secret'   # not in argv or shell history
authhound-probe radius test --server radius.corp.com --peap alice

Recipe: check your BlastRADIUS exposure

Have the full log open? Paste it here

The analyzer recognizes 19 common failure signatures and ranks the likely causes for your specific output. It runs entirely in your browser — nothing is uploaded.

This failure is usually invisible until users complain. AuthHound is building continuous monitoring that catches it first — early access:

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