Helpful Hints...
UPnP helps other UPnP LAN hosts interoperate with the router.
Leave the UPnP option enabled as long as the LAN has other UPnP
applications.
For added security, it is recommended that you disable the WAN
Ping Respond option. Ping is often used by malicious Internet users
to locate active networks or PCs.
The WAN speed is usually detected automatically. If you are
having problems connecting to the WAN, try selecting the speed
manually.
If you are having trouble receiving multicast streams from the
Internet, make sure the Multicast Streams option is enabled.
More...