The nfsd operates at port 2049, both udp and tcp protocols. The port mapped at port 111, tcp and udp, and mounted at port 745 and 747, tcp and udp. Normally. You should check the ports with the rpcinfo -p command.
of other software that check ports.

If on the other hand you want NFS to go through a firewall there are options for newer NFSds and mounts to make them use a specific (nonstandard) port which can be open in the firewall.

in DSS you may check option "Insecure" - the DSS will listen on higher ports for NFS mount requests
in DSS there is no option to specify this port.
DSS just uses random port from 1024-65536 if insecure option is checked.