Comment 14 for bug 1568560

Not sure I agree with #13 because message comes AFTER network is up:

Dec 13 05:52:20 alien NetworkManager[902]: <warn> [1513169540.4985] platform-linux: kernel support for IFLA_INET6_ADDR_GEN_MODE failed to detect; assume no support
Dec 13 05:52:20 alien NetworkManager[902]: <info> [1513169540.4991] manager: (enp59s0): new Ethernet device (/org/freedesktop/NetworkManager/Devices/0)
Dec 13 05:52:20 alien NetworkManager[902]: <info> [1513169540.4998] keyfile: add connection in-memory (f1d049d0-ad20-3201-ac70-5cb8cc06a6e5,"Wired connection 1")
Dec 13 05:52:20 alien NetworkManager[902]: <info> [1513169540.5001] settings: (enp59s0): created default wired connection 'Wired connection 1'
Dec 13 05:52:20 alien NetworkManager[902]: <info> [1513169540.5007] device (enp59s0): state change: unmanaged -> unavailable (reason 'managed') [10 20 2]
Dec 13 05:52:20 alien NetworkManager[902]: <info> [1513169540.5025] device (enp59s0): link connected
Dec 13 05:52:20 alien kernel: alx 0000:3b:00.0 enp59s0: NIC Up: 1 Gbps Full
Dec 13 05:52:20 alien NetworkManager[902]: nm_device_get_device_type: assertion 'NM_IS_DEVICE (self)' failed
D

Ubuntu 16.04.3, Kernel 4.14.4, Skylake laptop. IPv6 disabled with kernel command line in grub just because it life seems simpler that way. Only a couple of minor network interruptions requiring reboot over the last month.