Why doesn DCC send work behind a router (IPNat/ADSL)?
If you are behind a IP-NAT or ADSL router, you will most likely have an address like 192.168.0.1. This address is not usable on the Internet, and must be translated. When offering a DCC file, xchat will tell the receiver your address. If it says 192.168.0.1, the receiver will not be able to connect. One way to make it send your “real” address is to enable the “Get my IP from IRC Server” option in xchat. This option is available in Preferences -> File Transfers. When you turn it ON, you will have to re-login to the server before it’ll take effect. You will also need to forward some ports for use in DCC send.