NAS on Gateway NOK 5G21

iinnkk wrote:

How do I attach a hard drive or SSD to my T-Mobile Gateway (NOK 5G21)?

Use a NAS (Network Attached Storage) with an ethernet port, and plug it directly into the gateway’s ethernet port using an ethernet cable.

https://community.t-mobile.com/tv-home-internet-7/synology-nas-connection-41919

To add to tomwil's answer - once you connect your NAS you can you the t-mobile internet app (not the regular account app) and see your NAS and its IP under the devices tab. I would be nice if you could make this a static IP but doesn't seem to be possible