Backing up PC to wx4100 on another network

I have an WD EX4100 and I want to backup my laptop to a folder within my EX4100 which I have access to but ill be away from home, therefore on another network,

The software that creates backup works fine while on the same network as the EX4100 is on, but unable to see the EX4100 otherwise. I have got a mydns which is and points to my public IP address of my router


There are a lot of thing you need to setup. You might want to read on how to setup a local home VPN or port forwarding. I am not suggesting on port forwarding as it expose to internet that hacker can gain your home router/data.