WebSocket 1006 Abnormal Closure vs 1011 Internal Error
Both WebSocket 1006 (Abnormal Closure) and 1011 (Internal Error) belong to the WebSocket Close Codes category. 1006 indicates 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. Meanwhile, 1011 means that the server is terminating the connection because it encountered an unexpected condition that prevented it from fulfilling the request.
説明
A reserved value indicating the connection was closed abnormally without a Close frame being sent. This code must not be set by an endpoint.
このコードが表示される場合
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.
解決方法
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.
説明
The server is terminating the connection because it encountered an unexpected condition that prevented it from fulfilling the request.
このコードが表示される場合
The server hit an unhandled exception or crashed while processing a WebSocket message. This is the WebSocket equivalent of HTTP 500 Internal Server Error.
解決方法
Check the server-side application logs for stack traces and exceptions. Fix the underlying bug that caused the crash and add proper error handling around message processing.
主な違い
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.
WebSocket 1011: The server is terminating the connection because it encountered an unexpected condition that prevented it from fulfilling the request.
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.
You encounter 1011 when the server hit an unhandled exception or crashed while processing a WebSocket message. This is the WebSocket equivalent of HTTP 500 Internal Server Error.
どちらをいつ使うか
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. For 1011 (Internal Error): Check the server-side application logs for stack traces and exceptions. Fix the underlying bug that caused the crash and add proper error handling around message processing.