port forwarding query

I have the auto script installed,(silverfox0786) static IP address fixed, connection to dyndns.org working and resolving, ssh connection working...
i`ll be adding the oscam config files soon, however i`m unsure of port forwarding. I think i need to close all ports to the server apart from
1. for dyndns to communicate on both protocols ( my router vmdg280 doesnt have specific dyndns settings)
2. for oscam to run on both protocols

So my thinking is close all ports apart from 2 !!!

I this right ?, any help greatly appreciated