Bug#905503: networkd doesn't like fritzbox' IPv6 announcement, interface degraded

Marc Haber mh+debian-bugs at zugschlus.de
Fri Aug 10 19:29:51 BST 2018

fixed 905503 237-3~bpo9+1
fixed 905503 239-7

On Sun, Aug 05, 2018 at 03:49:37PM +0200, Marc Haber wrote:
> In the next days, I hope I will be able to reproduce this in a simpler
> test machine and then check whether the issue is still present in buster
> or sid. Sadly, it is becoming increasingly painful to run
> systemd-networkd in stretch.

I was able to reproduce this issue in stretch on an amd64 VM with the
following networkd configuration:



The Fritzbox assigns and IPv4 address and announces an IPv6 prefix. WIth
the systemd in stretch, networkctl hangs at "degraded/failed", while the
systemd 237-3 from stretch-backports and systemd 239-7 works, resulting
in the following network configuration:

2: ens3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 52:54:00:a8:3e:97 brd ff:ff:ff:ff:ff:ff
    inet brd scope global dynamic ens3
       valid_lft 861566sec preferred_lft 861566sec
    inet6 2001:db8:3022:4100:5054:ff:fea8:3e97/64 scope global mngtmpaddr noprefixroute dynamic 
       valid_lft 6880sec preferred_lft 3280sec
    inet6 fe80::5054:ff:fea8:3e97/64 scope link 
       valid_lft forever preferred_lft forever

default via dev ens3 proto dhcp src metric 1024 dev ens3 proto kernel scope link src dev ens3 proto dhcp scope link src metric 1024 

2001:db8:3022:4100::/64 dev ens3 proto ra metric 1024  pref medium
2001:db8:3022:4100::/56 via fe80::cece:1eff:x:y dev ens3 proto ra metric 1024  pref medium
fe80::/64 dev ens3 proto kernel metric 256  pref medium
default via fe80::cece:1eff:x:y dev ens3 proto ra metric 1024  mtu 1492 pref medium

The Fritzbox is an extremely common DSL router in middle europe, and
dual-stack networking is becoming increasingly common. Deutsche Telekom
and 1&1, two of Germany's largest ISPs for consumer DSL, both provide
dual-stacked Internet. This issue should be addressed in stretch.

I'll keep the test VM around for a few months, so that I can test
tentative fixes.


Marc Haber         | "I don't trust Computers. They | Mailadresse im Header
Leimen, Germany    |  lose things."    Winona Ryder | Fon: *49 6224 1600402
Nordisch by Nature |  How to make an American Quilt | Fax: *49 6224 1600421

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