AuthHound

RADIUS attribute 40 · type integer

Acct-Status-Type

Acct-Status-Type (attribute 40) says what an accounting record is: Start (1) when a session begins, Stop (2) when it ends, Interim-Update (3) for periodic usage snapshots.

Also searched as: Accounting Start Stop, Acct-Status-Type Interim-Update. Defined in RFC 2866.

What it means

Every RADIUS Accounting-Request declares its purpose through Acct-Status-Type. Start opens a session, Stop closes it (carrying the session's totals and a termination cause), and Interim-Update reports usage mid-session. Accounting-On (7) and Accounting-Off (8) signal a NAS reboot, telling the server to close any sessions it thought were still open on that device.

How it's used

Read it to drive session state in your accounting store. A missing Stop (NAS lost power, packet dropped) leaves a session open forever — Accounting-On from the rebooted NAS is the signal to clean those up.

Values

  • 1 — Start — a session has begun.
  • 2 — Stop — a session has ended (includes final counters).
  • 3 — Interim-Update — periodic mid-session usage report.
  • 7 — Accounting-On — the NAS has (re)started; close its stale sessions.
  • 8 — Accounting-Off — the NAS is shutting down.

Common gotchas

  • Lost Stop packets are normal at scale; rely on Interim-Update and Accounting-On to reconcile, not on Stop always arriving.

When a NAS quietly stops honoring an attribute across a fleet, nobody sees it until users complain. AuthHound is building monitoring that tracks the attributes your servers actually return — early access:

No spam, no sharing — one email when it's ready, and you can reply to be removed anytime.