Like every database system Netezza also uses its default port number until or unless you have changed it to a different port number.
Here is the details about default TCP/IP port numbers that Netezza uses and for why purpose:
Port number 5480 –> This port is used by Netezza for nzsql, postgres, NzAdmin tools and for ODBC & JDBC connections
Port number 5481 –> This port is used by Netezza for CLI and NzAdmin tool messaging connections
Port number 5482 –> This port was used for NzLoad in NPS version 3.1 and lower. For NPS versions higher than 3.1, this port is no longer used
Port number 5483 –> This port is used by Netezza for nzbackup and nzrestore commands
Additionally Netezza uses ssh22 for Netezza support team to remotely connect to your server to work on issues. It depends on organisations security policy if they want to open this port or not.
Also, for IBM to have ftp access to your box to copy Netezza logs, etc (while working on PMR’s) you have to open ftp port 20 & 21.