Synology Firewall Rules

Hi.
I have a trial version of Studio running on my Synology DS916+, running latest version DSM 7, with the remote on iphone.
Everything works fine, as long as I disable my final firewall rule on the Synology of deny all. It is literally like a switch if I enable and then disable it.
The first firewall rule is allow 1900 on UDP & TCP (just to be sure)
what are the server and remote ports that I need to allow?
I don’t want to leave my NAS unsecured!

Thanks