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What the UDP / QUIC / HTTP/3 chips on a proxy mean

You might be here because: “what does the UDP chip mean” · “QUIC falls back to HTTP/2” · “no UDP through this proxy” · “HTTP/3 not measured yet” · “why is QUIC grey” · “UDP not on plan”

Short answer

The chips say whether UDP traffic, and HTTP/3 (QUIC) on top of it, get through this proxy. UDP works means WebRTC calls and media stream through the exit. No UDP means HTTP/3 is switched off for the session and WebRTC uses a slower fallback. A grey or “—” chip means not measured yet — never “no”.

Check first

  • Has the proxy been tested with the full check? The quick test does not check UDP/QUIC.
  • Did you change the proxy’s address, type or credentials? That resets the readings to not-measured.

Likely causes and fixes

  1. “HTTP/3 works.” / “✓ QUIC” — QUIC got through on the last test, or a live session used HTTP/3.
  2. “HTTP/3 falls back to HTTP/2.” / “⤵ QUIC” — measured and did not get through; sites use HTTP/2 instead. Nothing to fix on Driftstack’s side; it is what the proxy carries.
  3. “HTTP/3 is likely to work (not yet measured).” / “~ QUIC” — inferred from a UDP grant, not measured.
  4. “HTTP/3 has not been measured yet.” / “— QUIC” — run the full check. If the hint says “Driftstack was busy”, retry in a few minutes.
  5. “worked when last checked” / “fell back when last checked” — an aged reading; run the check again for a current one.
  6. “UDP — not on plan” / “QUIC — not on plan” — VPN proxies are on paid plans, so this tunnel is not tested. See OpenVPN/WireGuard not included on this plan.
  7. VPN rows: “UDP through this tunnel has not been measured yet.” UDP travels inside the VPN; Check VPN measures QUIC through it.

A live session’s HTTP/3 result outranks the test’s, and the two are dated separately, so they can disagree for a while after a provider changes what it carries.

If it still fails

Nothing here needs support unless a chip contradicts what a session does; then press Talk to a person in this chat (or open Help) and include the proxy label and both readings.