What does errno 54 (ECONNRESET) mean?

ECONNRESET

A reset terminated the connection state

ECONNRESET indicates that the connection was reset rather than closed through the normal half-close and FIN sequence. In TCP, reset processing discards connection state and outstanding queued operations receive reset outcomes; it is therefore materially different from receiving an orderly end of stream.

The name “by peer” in a platform error description should not be simplified to “the remote application intentionally closed it.” A reset can be produced by protocol state, a remote stack, an intermediary, or an error path. The application needs packet, endpoint, and timing evidence before assigning blame.

What distinguishes it in logs

• Record whether the error appeared on read, write, or a pending connect; the same reset has different application consequences at each point.
• Capture the connection's four-tuple, protocol state, bytes acknowledged at the application layer, and any peer or proxy logs available for the same interval.
• Do not confuse a zero-length stream read after FIN with a reset. A graceful close and a reset require different retry and replay decisions.

Safe recovery question

Before reconnecting, establish whether the application operation was acknowledged. TCP reset semantics do not tell an application whether a request was processed before the transport failed.

References

• XNU: Darwin errno definitions
• RFC 9293: reset generation and processing
• POSIX: recv()

Looking for a different code? Search another status or error code.