WebSocket 1000 Normal Closure vs 1006 Abnormal Closure
Both WebSocket 1000 (Normal Closure) and 1006 (Abnormal Closure) belong to the WebSocket Close Codes category. 1000 indicates that the connection has been closed cleanly, meaning the purpose for which it was established has been fulfilled. Both endpoints agree the session is complete. Meanwhile, 1006 means that a reserved value indicating the connection was closed abnormally without a Close frame being sent. This code must not be set by an endpoint.
설명
The connection has been closed cleanly, meaning the purpose for which it was established has been fulfilled. Both endpoints agree the session is complete.
이 코드를 보게 되는 경우
The WebSocket connection closed gracefully after both sides finished exchanging data. This is the expected close code for a successful session.
해결 방법
No fix needed — this indicates everything worked as intended. If you did not expect the connection to close, check your application logic for premature close() calls.
설명
A reserved value indicating the connection was closed abnormally without a Close frame being sent. This code must not be set by an endpoint.
이 코드를 보게 되는 경우
The TCP connection dropped unexpectedly — the server crashed, the network cable was unplugged, or a firewall killed the idle connection. No proper WebSocket Close handshake occurred.
해결 방법
Implement reconnection with exponential backoff. Use WebSocket ping/pong frames to detect dead connections early. Check for network-level timeouts or aggressive load balancer idle limits.
주요 차이점
WebSocket 1000: The connection has been closed cleanly, meaning the purpose for which it was established has been fulfilled. Both endpoints agree the session is complete.
WebSocket 1006: A reserved value indicating the connection was closed abnormally without a Close frame being sent. This code must not be set by an endpoint.
You encounter 1000 when the WebSocket connection closed gracefully after both sides finished exchanging data. This is the expected close code for a successful session.
You encounter 1006 when the TCP connection dropped unexpectedly — the server crashed, the network cable was unplugged, or a firewall killed the idle connection. No proper WebSocket Close handshake occurred.
언제 어떤 것을 사용할지
For 1000 (Normal Closure): No fix needed — this indicates everything worked as intended. If you did not expect the connection to close, check your application logic for premature close() calls. For 1006 (Abnormal Closure): Implement reconnection with exponential backoff. Use WebSocket ping/pong frames to detect dead connections early. Check for network-level timeouts or aggressive load balancer idle limits.