Netgear .. at least the newer models of recent years have UPnP turned on by default. However, your Webstar ... even though you only use it as a modem ... I have a suspicion it may well have an internal NAT firewall.

To answer your question from a PM, when I first started using LW several years ago, the larger % of users were blocked behind firewalls & it was very difficult to download from people. So thus, the sharing network was limited. The LW programmers have done their utmost since then to over-come this. One has been to give LW UPnP abilities so it can communicate directly with UPnP capable & enabled routers & modems so it sends a request to open a particular port whilst the program is open. Only one program can access a particular port at a time & portforwarding or upnp only has the port open whilst the program is open. LW team also introduced the ability for windows users to configure their windows firewalls via LW. They also introduced a mechanism that lets LW detect if there is a firewall blocking it & to warn you. Before many, too many people were ignorant to the fact they may have had firewall probems affecting their use of LW. The overall aim is for people to configure their LW & firewalls so that sharing can take place without issues.