When connect(2) fails because the peer is not listening the virtio vsock transport returns ECONNRESET. I believe the VMCI transport does the same (based on code inspection). Jorgen: Can you confirm this VMCI transport behavior? I'd like to change to ECONNREFUSED for all transports because developers will be surprised when they get ECONNRESET. It makes porting AF_INET code harder. On the other hand, it may be too late to fix this if there userspace applications that rely on ECONNRESET? I'm not aware of any such applications myself. Thanks, Stefan