Kopete/Firewall
If you are behind a firewall or a NAT, you have to open ports (and redirect) some ports to use advanced feature of Kopete.
MSN
To use MSN file transfers and MSN webcam, you have to open port (and redirect) 6891 to inbound TCP traffic.
Port 6891 is by default, but it is configurable.
We don't use (yet) a reflector. (A server in the middle of the transaction) That protocol is fully encrypted to keep out others to use it, but the amsn team may have already decrypted it.