If you perform a security check by using a port scanner such as Nessus, the PowerExchange Listener might hang indefinitely on the main Listener port or ignore commands if a Listener port for a netport job is also defined. The problem occurs when a call to the TCPIP accept() function on the netport port is blocked until a connection is present. While the netport port is blocked, the main PowerExchange Listener port is never polled, so that non-netport requests appear to be hung. The Listener remains in this state until a subsequent netport request unblocks the netport port.
If this situation occurs, include the TCPIP_ACCEPT_NONBLOCK=Y statement in the DBMOVER configuration file on the Listener machine. This statement makes the PowerExchange Listener listening ports nonblocking, so that the accept() call can return a suitable status if it fails.