Budbobob
You have not revealed the model number of your modem, I say this because most modem/routers have built in firewalls and the only way to get LW and your modem/router to work together is to perform a "port forward" (configuration) exercise specific to the make and model of your modem.
The following link will take you to the PORT FORWARDING website, from there you will have to find the make and model of your modem/router.
PortForward.com - Free Help Setting up Your Router or Firewall
Good Luck
UK Bob