for ports

you need to dive in to your routers settings and forward ports to your pc.
from what i remember dplay ports were 2302-2400 udp/tcp and 6073udp. but that may not be necessary.
you need to forward these ports to your local ip (possibly something like 192.168.x.x)

for your IP, see whatismyip.org or again in your routers control panel, it should be written somewhere

edit: didnt see the previous 2 posts >.<