Problems configuring pppoe when using netplan

[Jane Atkinson]

Before updating my router running ubuntu server 16.04, I've been running some tests with ubuntu server 18.04 in VMs, to make sure that netplan will do what I want it to.

The internet connection with my ISP uses pppoe.

I can get pppoe to work by configuring manually, but the simplest way to set it up is with pppoeconf. However, installing pppoeconf pulls in ifupdown, which I assume isn't desirable when using netplan.

I can use pppoeconf to do the user settings, then remove it along with ifupdown. That leaves the user settings intact, and with the correct .yaml configuration, pppoe will then work with netplan.

This seems unnecessarily complicated. pppoeconf should no longer have ifupdown as a dependency. If ifupdown is needed, it is very likely to be already installed on the server. If it's not, it can be installed separately.

[Ryan Harper (raharper)]

Thanks for the bug report.

Currently pppoe support in networkd is unavailable at this time[1]
However, NetworkManager has support for pppoe[2], so it could be possible to work on the yaml structure needed for pppoe configuration,

Then, at least drive the NM backend, but the networkd will need an implementation.

For now, if you need pppoe support on Bionic, it's still driven from ifupdown configuration.

1. https://github.com/systemd/systemd/issues/481
2. https://developer.gnome.org/NetworkManager/stable/settings-pppoe.html

[Steve Langasek (vorlon)]

fwiw I am currently using networkd-dispatcher for this with the following scripts:

$ cat /etc/networkd-dispatcher/routable.d/ppp
#!/bin/sh

set -e

if [ "$IFACE" != wan ]; then
        exit 0
fi

pppd call centurylink

sleep 5

ip route change default dev ppp0 advmss 1482
$

$ cat /etc/networkd-dispatcher/no-carrier.d/ppp
#!/bin/sh

set -e

if [ "$IFACE" != wan ]; then
        exit 0
fi

if [ -e /run/ppp-centurylink.pid ]; then
        pid=$(cat /run/ppp-centurylink.pid)
        kill "$pid"
fi
$

With symlinks for the no-carrier.d script under dormant.d, off.d, and degraded.d.

While ideally this would be implemented directly in netplan, perhaps the above will be useful to someone who finds this bug.