One of our programmers setup an application on 100 computers (same subnet) that relays email off our exchange 2007 server to internal and external recipients. Rather then setup an receive connector that allows anonymous access to entire subnet, is there a way to setup a new recieve connector that will only allow 3-6 domain users (the program uses the same email accounts to send the emails) to connect on port 25 and send mail from any of those 100 computers to internal and external recipients. Originally, I setup an anonymous relay connector and explicitly defined the ips but there are simply too my ip's to list at this point. I also don't want to allow the entire subnet to relay mail off our exchange server. Any help would be greatly appreciated.