UPNP
one alternative to foreward port is using UPNP. if your router support it then you can use simple program and library to forward port automatically
without someone open it for you, Universal plug and play support networking with protocol like tcpip,http,soap
http://www.codeproject.com/KB/IP/upnpnattraversal.aspx?msg=2706732
there's a library called mono .Nat that is deserved to have a look
http://projects.qnetp.net/wiki/mono-nat/API_Reference