Also affects ubuntu 11.10. Here's what was happening: my wifi interface was showing up as up but unmanaged (this is a very fresh installation, so that's how the installer left it), and 'route' showed
Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface default 192.168.0.1 0.0.0.0 UG 0 0 0 eth0 default 192.168.0.1 0.0.0.0 UG 100 0 0 wlan0 link-local * 255.255.0.0 U 1000 0 0 eth0 192.168.0.0 * 255.255.255.0 U 0 0 0 wlan0 192.168.0.0 * 255.255.255.0 U 1 0 0 eth0 The command 'ifconfig wlan0 down' fixed the problem! After that, the routing table was Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 192.168.0.1 0.0.0.0 UG 0 0 0 eth0 169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 eth0 192.168.0.0 0.0.0.0 255.255.255.0 U 1 0 0 eth0 and everything was hunky-dory. So the problem was that the installer left my system in an inconsistent state: wlan0 was up but not managed, and acted as a packet /dev/null 35 seconds out of every 43 seconds. ** Package changed: ubuntu => network-manager (Ubuntu) -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to network-manager in Ubuntu. https://bugs.launchpad.net/bugs/917399 Title: Ubuntu 12.04 alpha 1 network flaky after update Status in “network-manager” package in Ubuntu: New Bug description: Testing 12.04 alpha 1 64 bit on my Asus G60JX laptop. Worked well enough with previous versions ( http://kegel.com/linux/asus-g60jx-laptop.html ). As with previous versions of Ubuntu, the Live CD / normal desktop installer couldn't get graphics right, so used alternate install iso, and had to specify "nomodeset" on kernel commandline after installation to get any graphics. Was able to do a complete software update, then rebooted. After that, networking seemed flakier. When I try downloading the nvidia display driver with "Additional Drivers", the download seems to hang after a few seconds. Rebooting and retrying doesn't help. There were several crashes, and apport collected data for them and even uploaded one of them, but I was unable to finish the login process at launchpad. I had to reboot to 11.04 to file this report. This is all with wired networking, as wireless doesn't work at all. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/917399/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp