Comment 10 for bug 379166

in my case it's most probably a router issue. it's a crappy one:

gpon ECI B-FOCuS O-4G2Pw

sometimes while wireless seems to be connected fine, and even some torrents streaming properly, yet the router doesn't answer to ping, nor does DNS work.

breaking and reconnecting the wireless connection fixes it for a while, but if torrents are running, then it happens soon after.