The graph below shows an overview of the network traffic and the ports that need to be open to initiate the connections. The proxy uses two TCP ports to read data from other servers: 445 to read server-level performance counters from Windows registry and 1433 (default) to read instance-level and database-level counters from SQL server. Note that if the SQL Server instance is configured on another TCP port then that one should be opened in the firewall instead.
The Web API port is configurable, although the default port of 8201 is recommended. When adding servers to be monitored to a proxy, the SQL Server port can be configured if needed.