neqo — A second GOAWAY naming a larger identifier than the first

Fail

Rejected, but with error 0x101 where the specification requires 0x108. The violation was detected; the code reported is wrong.

The client did something the clause forbids, or failed to do what it requires.

What was measured

Client

neqo — neqo (Firefox), 0.31.1

Test

A second GOAWAY naming a larger identifier than the first — h-goaway-increasing

Clause

RFC 9114 §5.2 (MUST)

Class

correctness — Rejected something invalid, with the code the RFC names.

Required behaviour

Close the connection with H3_ID_ERROR. §5.2 permits multiple GOAWAY frames but requires the identifier in each to be no greater than any previously sent, because the identifier is a promise about what will still be processed and raising it takes that promise back. "Receiving a GOAWAY containing a larger identifier than previously received MUST be treated as a connection error of type H3_ID_ERROR."

Measured

2026-09-17

Reproduce it

The suite is the judge, so the reproduction is to point the same client at the same test and let the server report what it saw.

SESSION=$(curl -sX POST https://conformance.pqcrypta.com/session | jq -r .id)
# then drive neqo at the test URL and read the verdict:
curl -s https://conformance.pqcrypta.com/report/$SESSION.json | jq '.results["h-goaway-increasing"]'