the sender connect to the receiver computer
I see the obvious problem with this that the receivers firewall well then be incountered and so he well have to sort the problem out.
In the real world its one sender and lots of receivers, this makes it much more logical that the one sender sort his firewall out than the multiple receivers.
I assume your talking about a passive dcc, which can be already done in some ways as far as i know, but really how hard is it to sort a firewall/router out.