The device in question indeed does not have a 'scope global' address: https://en.wikipedia.org/wiki/Unique_local_address says that fd00::/8 is a 'unique local address'. I'm not sure why charmhelpers isn't happy to use them. Note, though that the description there says you probably shouldn't use fd00::/8 directly, but should use a randomly-generated prefix. Generally it seems like it is a charmhelpers issue, rather than a Juju issue. On Sat, Apr 28, 2018 at 3:39 AM, Michael Quiniola <