I have two NAS devices, one from Qnap, one from Synology, each in a different city and need to transfer tens of GB between them. The Synology is accessible through QuickConnect and the Qnap through myQNAPcloud and has their DDNS turned on.
I know it is possible to use rsync to transfer data between NASes of different brands, for example as discussed here. However, I do not know how to proceed when the devices are not in a shared network.
Could someone more experienced in this please turn me in the right direction? I have no idea how to make this work. This is a one-off task - I do not need to setup a long-term connection, I just need to transfer the data from the Qnap to the Synology.