>... it seems that the NS3000 client, >nvt, has a zero tcp checksum field. ...or am I missing >something. Yes... you're missing the TCP checksum :-). You need to make sure that TCP checksumming is enabled in NMMGR. The path is NETXPORT.GPROT.TCP, which means that once you've opened the configuration file in NMMGR, you can press the HOME key to get up to the command line, then type @NETXPORT.GPROT.TCP to get you to the right screen. I think the default is to disable TCP checksumming since it's not needed for data integrity over transport paths that already provide such integrity (like Ethernet). I believe that you'll need to restart the HP3000's network software to make the change take effect. (:NETCONTROL STOP followed by whatever sequence you use to bring up the network.) -- Bruce --------------------------------------------------------------------------- Bruce Toback Tel: (602) 996-8601| My candle burns at both ends; OPT, Inc. (800) 858-4507| It will not last the night; 11801 N. Tatum Blvd. Ste. 142 | But ah, my foes, and oh, my friends - Phoenix AZ 85028 | It gives a lovely light. [log in to unmask] | -- Edna St. Vincent Millay