Besides the common port of 19300 – 19xxx which you specify when setting up and installing Cognos Express, there are additional ports that will need to be allowed on the server in order for the Cognos Gateway webserver to work correctly.
The following firewall rules will need to be configured to open ports:
Inbound ports: 80, 389, 443, 636, 5495, 5498, 7113, 19300-19xxx
Outbound ports: 19300-19xxx
Example: Setting up Inbound Rules for Windows Firewall