Glad you have things working.
Here’s the list of ports to allow through the Synology firewall: What network ports do I need to allow through my firewall?
The only port you need to forward in the router is TCP/32400, and only if you want remote access.
FYI, if you ever update from DSM 6 to 7, first read FAQ 27 - Migrating an existing PMS from DSM 6 to DSM 7. Synology forced a lot of changes with DSM 7. It is not as simple as installing a new version of PMS.
