If you have a LAN, you need FQDN for the server.
ping /a YOUR_ROGERS_GATEWAY
You should see the FQDN like this, gw03-vlan-301.flfrd.phub.net.cable.rogers.com
then, use nntp.flfrd.phub.net.cable.rogers.com as your server.
To post msgs, you also need FQDN for your username.