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4

SSH_DISCONNECT_RESERVED

DisconnectRFC 4253 §11.1

SSH_DISCONNECT_RESERVED (4) is a reserved disconnect code in RFC 4253 §11.1. It has no defined meaning and should not be sent by implementations. It exists as a placeholder in the numbering scheme. If received, treat it as an unspecified disconnect.

Code

4

Category

Disconnect

Standard

RFC 4253 §11.1

Description

Code 4 is reserved in the RFC 4253 disconnect code table and has no assigned semantic meaning. Standards-compliant SSH implementations do not send this code. If a disconnect message with reason code 4 is received, the implementation should treat the disconnect as occurring without a specific reason.

The description string in the SSH_MSG_DISCONNECT message may provide human-readable context when a non-standard code like 4 is received.

Common Causes

  • Non-standard SSH implementation sending reserved code
  • Protocol implementation bug using code 4 instead of a valid code