Let me get this straight. We have a client attach to Server A (via http). During the handling of this request, it is determined that a connection to Server B is required to run some other program. Is that right?

So the question is - what protocol to use? That will entirely drive the module(s) that you can use/need. Do you connect via telnet, or ssh, or rsh, or something else? Perhaps Server B is also running a webserver, in which case your CGI script can just use LWP to connect and pass stuff in and get the returns back. But you have to determine how you want to make these connections.