This is happening for me as well on Ubuntu 15.04 (upgraded from 14.04 through 14.10).
Interestingly, i changed my wifi-card since first experiencing this, but it did not help. It had an rt2x00 driven USB adapter before and now run an Intel based PCIe card with exactly the same behaviour: Directly after boot, NM shows a connection but i cannot visit any website. I have to manually disconnect and connect again to get internet access. My network adapter: 05:00.0 Network controller: Intel Corporation Wireless 7260 (rev bb) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1434986 Title: Not working network connection after boot To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1434986/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs