The LDM only uses one port. By default, this port is 388. You should configure your firewall to allow traffic on port 388 to pass unhindered -- in both directions. Regards, Steve Emmerson Ticket Details =================== Ticket ID: YYC-951813 Department: Support LDM Priority: Normal Status: Closed From: "DL Wyche" <address@hidden> Institution: Lockheed Martin Corporation Package Version: N/A Operating System: Linux Hardware Information: Cisco PIX Inquiry: I am setting up a Cisco PIX firewall that will protect our secure DOD systems from a radar weather site where we will collect data. The Open RPG server inside our system uses the LDM protocol to initiate the data stream collection. My question is very simple. Does all communication occur using the port 388? If not what other ports are involved and are any of the other ports opened by the responding server outside the firewall? Thanks D. L. Wyche Sr. Systems Engineer Lockheed Martin Corp. 2050 S. Blosser Rd. Santa Maria, CA 93458 - 7310 805.348.2042 address@hidden