Ubuntu 22.04 - xl2tpd broken

[dkosovic]

xl2tpd-1.3.16-1 package that ships with Ubuntu 22.04 is broken, it will produce Can not find tunnel errors like the following :

Mar 31 12:00:12 NetworkManager[4991]: xl2tpd[4991]: Can not find tunnel 105 (refhim=0)
Mar 31 12:00:12 NetworkManager[4991]: xl2tpd[4991]: network_thread: unable to find call or tunnel to handle packet.  call = 39697, tunnel = 105 Dumping.
Mar 31 12:00:13 NetworkManager[4991]: xl2tpd[4991]: Can not find tunnel 105 (refhim=0)
Mar 31 12:00:13 NetworkManager[4991]: xl2tpd[4991]: network_thread: unable to find call or tunnel to handle packet.  call = 39697, tunnel = 105 Dumping.

The broken Ubuntu 22.04 xl2tpd package was first reported back on 2021-11-22 :

• https://bugs.launchpad.net/ubuntu/+source/xl2tpd/+bug/1951832

Hopefully a new xl2tpd packages will be released soon. Subscribe to that bug report if you wish to receive the latest news on a new xl2tpd package.

One workaround is to use Katalix go-l2tp. NetworkManager-l2tp >= 1.20.0 will use kl2tpd as the default L2TP daemon and fall back to xl2tpd if it can't find it, kl2tpd can readily be installed with :

sudo apt install golang-go

go install "github.com/katalix/go-l2tp/...@latest"
sudo mkdir /usr/local/sbin
sudo cp go/bin/kl2tpd /usr/local/sbin

[dkosovic]

Upstream xl2tpd bug report:

• Upgrading 1.3.12 to 1.3.16 breaks VPN connection xelerance/xl2tpd#230

[akarl10]

just tried to break my vpn in the same way as xelerance/xl2tpd#230 (comment) (well, I think so), by making a l2tp/ipsec server having the same ppp "inner" remote address as the vpn server itself.

Essentially this #132

ip r
VPN.SERVER. dev ppp0 proto kernel scope link src INNER.IP
VPN.SERVER. via LOCAL.DEFAULTGW dev eth0 proto static metric 50

the second one gets most probably added by nm, the first probably by pppd

But somehow this does not work (anymore? don't have a 20.04 to test on hand) in ubuntu 22.04

[dkosovic]

The ppp0 metric 0 (or no metric) route is the following NetworkManager 1.36.4 issue:

• https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/issues/961

If the VPN's inner and outer gateway are one and the same, it's definitely an upstream bug with NetworkManager >= 1.36.0, it shouldn't be adding that broken ppp0 metric 0 route.

[dkosovic]

To keep this issue on topic, if it is not related to the Can not find tunnel error as a result of the broken xl2tpd that ships Ubuntu 22.04, please submit a new issue even if it is for Ubuntu 22.04.

[dkosovic]

This bug was fixed in the package xl2tpd - 1.3.16-1ubuntu0.1

---

xl2tpd (1.3.16-1ubuntu0.1) jammy; urgency=medium

• Disable LTO to make the package work again (LP: #1951832).

-- Robie Basak robie.basak@ubuntu.com Thu, 28 Apr 2022 12:01:14 +0000