I'm trying to send binary data from a Flex application to an external proprietary server that will then issue a response in binary. The ip address and port number I'm sending to is simply a listening socket - not a web server. I had thought I could do this using the Socket class but I hit the security sandbox violation issue. Does a Flex socket have to connect to a web server? If so then I probably can't do things in this way. I've Googled for a couple of days on this but nowhere talks about doing this sort of thing.