Is my NAS accessible from the Internet?

I have a FreeNAS server set up to do nightly backups for my various Windows machines. I turned SSH on to make administration a little easier - I have plenty of Linux VMs and it's easier for me to SSH in and do administrative tasks (e.g. running badblocks for the first time on new drives) from there.

All my systems are behind a Netgear router which does not have port fowarding, DMZ, or anything else of that kind enabled. Am I correct in believing that it is impossible for anyone to SSH into (or otherwise access) my NAS outside of the local network? I can't, but for all I know, there's some kind of attack or packet spoofing that would make it possible.

Thanks!

By default, it is not possible to access your NAS from the Internet, because you haven't setup port forwarding or a DMZ.

If someone is able to hack into your computer (by means of spyware/trojan virus/etc) they can get onto the NAS from there. If they get on your PC, they usually can access all your data. You should not be worried about this unless you have no antivirus software. I just mention this to be thorough.