Explicit check for address type, now check if an addr passed is IPv6. Otherwise, network var will remain empty.

cmd/dwelling-upload/main.go

@@ -52,7 +52,7 @@ func main() {
 
 		if ap.Addr().Is4() {
 			network = "tcp4"
-		} else {
+		} else if ap.Addr().Is6() {
 			network = "tcp6"
 		}
 	}