The CMPFILDTA command uses a communications port based on the port number specified in the transfer definition. If you need to run simultaneous CMPFILDTA jobs, you must open the equivalent number of ports in your firewall. For example, if the port number in your transfer definition is 5000 and you want to run 10 CMPFILDTA jobs at once, you should open at least 10 ports in your firewall—minimally, ports 5001 through 5010. If you attempt to run more jobs than there are open ports, those jobs will fail.