Arch Linux

networkmanager-1.2.0-2 switched to using the internal dhcp client as default. The internal dhcp client hangs in a mixed SLAAC/DHCPv6 environment, such as when using SLAAC for addresses as normal but advertising DHCPv6 for supplementary configuration (DNS/NTP/SNTP), as provided by many (if not most) IPv6-capable home routers.

This is fixed upstream by a patch [1] on both master and nm-1-2 branches and will be in NetworkManager 1.2.1, however with the release date for 1.2.1 not scheduled I think it would be best to include this patch in our 1.2.0 package if the default configuration is going to be `dhcp=internal`.

[1] https://cgit.freedesktop.org/NetworkManager/NetworkManager/commit/?h=nm-1-2&id=50dc5fecabc2c3434d7a652b4f5642556b4e87bf


Additional info:
networkmanager-1.2.0-2

Steps to reproduce:
1. Be on a mixed SLAAC/DHCPv6 environment (e.g., the router advertisements indicate stateless address configuration but stateful "other" configuration).
2. Connect to that environment with NetworkManager while requiring IPv6 addressing for that connection.
3. Watch NetworkManager's state never resolve. Note that the connection will usually still be functional after a few seconds, but NetworkManager will still advertise it as not being connected, causing many modern desktop applications to default to offline mode.