no network inside Docker containers

[Nagy Ferenc László]

There's no network inside Docker containers in Ubuntu 15.10.

Steps to reproduce:
1, Install Ubuntu 15.10
2, Install docker.io package
3, Execute "sudo docker run -it ubuntu:14.04"
4, At the container's root prompt execute "ping www.ubuntu.com" or "ping 91.189.89.110"

Expected results:
ping gets replies from the server

What happened instead:
ping fails: "ping: unknown host www.ubuntu.com"
or (when pinging the IP address): "From 172.17.0.2 icmp_seq=1 Destination Host Unreachable"

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: docker.io 1.6.2~dfsg1-1ubuntu4
ProcVersionSignature: Ubuntu 4.2.0-16.19-generic 4.2.3
Uname: Linux 4.2.0-16-generic x86_64
ApportVersion: 2.19.1-0ubuntu3
Architecture: amd64
CurrentDesktop: Unity
Date: Sat Oct 24 21:13:06 2015
InstallationDate: Installed on 2015-10-24 (0 days ago)
InstallationMedia: Ubuntu 15.10 "Wily Werewolf" - Release amd64 (20151021)
SourcePackage: docker.io
UpgradeStatus: No upgrade log present (probably fresh install)

[Nagy Ferenc László (nfl)]

Network used to work as expected in 15.04.

[Nagy Ferenc László (nfl)]

As written in bug #1509867, the network is fine after docker restart.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.