Ports to open on firewall appliance

Hello All,
I'm new in this forum, and i'm very happy to connect with all members of this forum.
I'm networh engineer, and BDD team need to access to db oracle server remotely in branch offices, and they need to execute directly with toad any scripts to update,modify or read data ..
So i know the default port is 1521, but just configured only this port on firewall don't allow connection to the database, so i allowed any services (first), users are connected and then i have seen many random ports are opened. my question is there any limited range of this random ports to add it with 1521 port .
thanks you