Comment 23 for bug 1271144

As a counterpoint, it worked for me with juju 1.18.1:

$ juju status
environment: scapestack
machines:
  "0":
    agent-state: started
    agent-version: 1.18.1
    dns-name: some.node
    instance-id: /MAAS/api/1.0/nodes/node-some-uuid
    series: precise
services: {}

$ juju ssh 0 ifconfig br0
br0 Link encap:Ethernet HWaddr aa:aa:aa:aa:aa:aa
          inet addr:1.2.3.4 Bcast:1.2.3.255 Mask:255.255.255.0
(...)

Is your bootstrap node on precise or trusty?