Updated Date: 07/07/2026
Description of log levels for QUIC log messages
This table describes each log level and gives some examples of messages that might be logged for each log level.
| Level | Description | Sample log messages |
|---|---|---|
| Critical | Non-protocol-related errors that would preclude healthy operation of the traffic filter. | ``` hud_quic_init errors quic_init errors TLS errors Stream initialization errors Closing connection with INTERNAL_ERROR ``` |
| Error | Protocol-related errors that would prevent a connection from proceeding as expected. | ``` Encrypt/decrypt errors; AEAD errors CONNECTION_CLOSE that is not of error_code=0x0 (NO_ERROR) Packet parsing errors Frame parsing errors Packet drops due to parsing or memory allocation issues Host unreachable ``` |
| Warning | Protocol-related issues that don't necessarily violate the spec, but which may result in sub-optimal connection. | ``` Missing transport parameters Address validation errors ``` |
| Notice | Connection-level logging. | ``` New connection established (log src, dst IP:port and connection IDs, token) Connection state changes (transition from initial->handshake->1-RTT) Congestion control enabled/disabled Connection terminated Retry limits (or other thresholds exceeded, similar to SYN cookie activation/deactivation) Initiation of address or path validation Success/Failure of path validation (and reason for failure) Sending VN Connection migration detected Connection lookup messages Packet drops due to being in the wrong state ``` |
| Info | Stream-level logging. | ``` Stream establishment Stream state changes Stream reset/close ``` |
| Debug | Other. | ``` TLS key material Log secrets, sufficient to generate an SSLKEYLOG file for use with wireshark xbuf_move errors Other miscellaneous logging ``` |