This topic is only applicable to the grid version of Symphony.
You need to open up a few ports (vemkd, Session Director, session manager) in the firewall for the client to interact with the grid. The client first communicates with the vemkd and gets the port information of the Session Director. The client then connects to the Session Director and gets the port information of the session manager and then connects to the session manager. It is important to set appropriate port ranges for session managers because there may be multiple session managers in a Symphony grid.