Specify how daemons are to connect back to the NetBackup Client daemon (BPCD):
Use default connect options
Use the value that is defined in the Firewall host properties of the client's NetBackup server.
See Default connect options.
Random port
NetBackup randomly chooses a free port in the allowed range to perform the legacy connect-back method.
VNETD port
NetBackup uses the vnetd port number for the connect-back method.