No VPN connectivity when accessing tunnel endpoint over IPv6

[James Page]

Our VPN provides both IPv4 and IPv6 addresses for the tunnel endpoint. With the latest openvpn on Bionic, the VPN starts, but no network connectivity is actually established if the client is accessing from an IPv6 enabled location; forcing the tunnel endpoint to IPv4 (using its IP address) resolves the issue.

This worked until very recently.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: openvpn 2.4.4-2ubuntu1
ProcVersionSignature: Ubuntu 4.15.0-10.11-generic 4.15.3
Uname: Linux 4.15.0-10-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.8-0ubuntu10
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Thu Mar 15 10:06:12 2018
InstallationDate: Installed on 2016-11-06 (493 days ago)
InstallationMedia: Ubuntu 16.10 "Yakkety Yak" - Release amd64 (20161012.2)
SourcePackage: openvpn
UpgradeStatus: Upgraded to bionic on 2017-11-16 (119 days ago)

[Launchpad Janitor (janitor)]

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

[Andres Rodriguez (andreserl)]

I hit the same issue and had to force the v4 address as well.

[Andreas Hasenack (ahasenack)]

Are you guys using just openvpn from the command line, or via the network-manager plugin?

FWIW, I use it via NM and have a script to disable ipv6 after the vpn is established. I found that disabling ipv6 in the plugin doesn't work (https://bugs.launchpad.net/ubuntu/+source/network-manager-openvpn/+bug/1738042).

[Adam Collard (adam-collard)]

> Are you guys using just openvpn from the command line, or via the network-manager plugin?

I was hitting this on two separate machines, both using the network-manager plugin, using the IPv4 address instead of a name worked perfectly

[James Page (james-page)]

I'm also using the network manager plugin for reference.

[Andreas Hasenack (ahasenack)]

ppa:ahasenack/nm-ipv6-openvpn-1758331 (https://launchpad.net/~ahasenack/+archive/ubuntu/nm-ipv6-openvpn-1758331/) has test packages with the upstream commit