Sounds like the port is not closing properly or not cleaning up after itself. I would suggest a timer be started at the beginning of the session and fire after the amount of time required for your process to force it to shut down. Most TCP type schemes like this would use two ports, one to make the original connection, then a seperate thread to handle that request so the original port could continue to listen for more connections. In this senerio you may want to use a multi threaded Dll.

Bob

>>Short answer is yes.
>>Keep in mind that the port can't be used by another app until you close it. If you tell me in more detail what are you trying to accomplish, I may be able to help you. Feel free to use my private email.
>
>Basically I have a VFP service that listens on a port. There is a 3rd-party client application that ongoingly picks up files from a directory and sends them to the specified port. All is well on the first send/receive, but after that the client application errors because it says that it is unable to communicate with the port. I have calls into the 3rd-party people, but there are not as responsive as people here are. <g>