(1) In what order do you run the commands? It's better to start the listening
nc before the connecting nc. (2) Are you sure the firewall on the listening side allows the incoming connection? (3) If you read with ntfsclone -s then the output is not a raw copy, it's a special format specific to the tool; so you need to write it with ntfsclone -r, just dumping the uncompressed stream to /dev/sda3 won't recreate the filesystem. (4) I don't know zstd, looks sane at first glance. // Conclusion: if you manage to connect nc to nc then you should certainly fix (3).