Time Machine to NAS, over internet I have a Synology DiskStation NAS that I use for Time Machine backups on my LAN. I want to be able to back up when I'm away from home. I've tried:


Connecting via L2TP VPN running on Synology
Connecting directly to Synology via AFP


Through both of these methods I can mount the Time Machine share in the Finder, and I've confirmed read/write access to the share when connected over the internet.

However, when I've mounted the share over the internet, and try to "Back Up Now," I get a message that it couldn't find the disk. Even though the disk is mounted.
Synology does have this walk-through for doing what you want to do.

I will mention that (quite some time ago) I used a Synology NAS as a time-machine target disk, and I did get it to work, but found it to be highly error-prone. Not what you want in a backup. Also slow. I'm using a drive with a direct USB3 connection now and am much, much happier with that.