This is correct, 1433 is default port for MS SQL server, but of course it might be changed.
You are asked to provide port during NAM server installation procedure. Please, take into account, that after changing the port on MS SQL side, you need to update configuration on NAM server side as well.
Hello @YC M.
The following link is a summary of network ports and protocols for various communication channels required for NAM Server, DC RUM 2017 ADS, NAM Probe, NAM Console, TCAM, and other components of NAM.