Question: I'm thinking about acquiring a NAS from Synology (or QNap), these are pretty cool NAS and do much more than just storing files.
Some extras include:

* ssh, ftp, telnet, mail servers
* photo gallery (directly from the NAS!)
* mysql/php (can even run a website from there)
* and much more

On the specs side it looks awesome as a LAN server but it's possible to access those services also from the Internet. And now, I'm wondering how safe that is, considering you're actually putting multiple servers and, not to forget, all your personal files stored in that device, *on the Internet*.

I've done a bit a research and ssh access could be hardened using 2-step authentication, but not sure about the other services, unless they all have to go through ssh?

I would appreciate your view on this and other possible ways to make your home NAS secure.

Answer: 
Don't put on the internet if you don't need it. If you do need it make all the other services only available locally and only allow ssh from the internet. You can then make a tunnel through ssh and access your other services through that tunnel.

Do mind that it is a ***HOME*** NAS so better keep it on your LAN.
Do you intend to put your family photos, music library, ripped DVD collection and house documents onto the NAS?

If so, how much would it matter to you if:

* They were all over the internet.
* They were all erased.

If either of these matter to you, you'd be best not to poke a hole in your firewall exposing this NAS to the internet.

If these things just don't matter, can you isolate the NAS from the rest of your home devices, e.g. a 'home DMZ'? In that way, if the NAS is compromised, your internet access and other home devices are not at risk.