In order to use nbdfuse with TLS it's necessary to add a call to nbd_set_uri_allow_local_file(), as shown in the below patch. However, I'm not familiar enough with the nbdfuse use-cases and motivation for the "allow local file" opt-in to know whether this really should be a command-line argument-based opt in. I'm guessing it should... diff --git a/fuse/nbdfuse.c b/fuse/nbdfuse.c index 628a75c..73eede4 100644 --- a/fuse/nbdfuse.c +++ b/fuse/nbdfuse.c @@ -539,6 +539,9 @@ create_and_connect (enum mode mode, int argc, char **argv) } nbd_set_debug (h, verbose); + /* Allow ?tls-psk-file and ?tls-certificates */ + nbd_set_uri_allow_local_file (h, true); + /* Connect to the NBD server synchronously. */ switch (mode) { case MODE_URI: