OK, guys.
I have the same problem with the DCC Send, but I know for sure that in my case the reason is that the ISP closed all DCC sending ports on input (2070-2075 or any other range).
In my case the ISP refuses to open any ports I request so my question is - is there any other way to solve this problem (some tricks, emulations, playing with settings, etc.)?

Sorry if my question may seem dumb to you, I'm not so experienced in network area.