What does Windows error code 1225 (ERROR_CONNECTION_REFUSED) mean?

ERROR_CONNECTION_REFUSED

A refusal is different from an unreachable network or host: the connection attempt reached a point where the remote side or its stack rejected it. At the application level, this often means no service is listening on the destination endpoint, a service is rejecting new connections, or a policy component is sending an explicit refusal.

For SMB diagnosis, establish whether TCP connection to the SMB service fails before SMB negotiate. If transport connects and SMB later returns a protocol status, preserve that SMB status instead of labelling it as a connection refusal. The protocol-stage boundary keeps firewall/listener problems separate from authentication and share errors.

Confirm the refusal stage

• Record destination address and port selected by the client.
• Determine whether the TCP connection was refused before any SMB message was exchanged.
• Check the remote listener/service state and host firewall policy.
• Compare with ERROR_PORT_UNREACHABLE and ERROR_HOST_UNREACHABLE; those are different failure classes.

Windows network redirector architecture · MS-SMB2 TREE_CONNECT · Samba smbclient manual