IPv6 static default route added incorrectly by network-manager

[Martin Jackson]

The relevant part of the IPv6 routing table looks like this:

fe80::/64 dev wlan0 proto kernel metric 256
default via fe80::5054:ff:fe64:aad0 dev wlan0 proto static metric 1
default via fe80::5054:ff:fe9c:741e dev wlan0 proto kernel metric 1024 expires 8sec
default via fe80::5054:ff:fe64:aad0 dev wlan0 proto kernel metric 1024 expires 10sec

I believe the proto static metric 1 route is an error, since it persists even when the router stops advertising. This breaks the IPv6 architecture for router redundancy.

I am in control of this network and can alter router advertisement parameters if needed.

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: network-manager 0.9.6.0-0ubuntu7
ProcVersionSignature: Ubuntu 3.5.0-22.34-generic 3.5.7.2
Uname: Linux 3.5.0-22-generic x86_64
ApportVersion: 2.6.1-0ubuntu10
Architecture: amd64
CRDA: Error: [Errno 2] No such file or directory: 'iw'
Date: Sat Jan 19 10:47:05 2013
InstallationDate: Installed on 2012-11-15 (65 days ago)
InstallationMedia: Ubuntu-Server 12.10 "Quantal Quetzal" - Release amd64 (20121017.2)
IpRoute:
 default via 192.168.4.1 dev wlan0 proto static
 169.254.0.0/16 dev wlan0 scope link metric 1000
 192.168.4.0/24 dev wlan0 proto kernel scope link src 192.168.4.64 metric 9
MarkForUpload: True
NetworkManager.state:
 [main]
 NetworkingEnabled=true
 WirelessEnabled=true
 WWANEnabled=true
 WimaxEnabled=true
RfKill:
 0: phy0: Wireless LAN
  Soft blocked: no
  Hard blocked: no
SourcePackage: network-manager
UpgradeStatus: No upgrade log present (probably fresh install)
WifiSyslog: Jan 19 10:17:54 pippin wpa_supplicant[1009]: wlan0: WPA: Group rekeying completed with 00:24:a5:f1:08:8e [GTK=CCMP]
mtime.conffile..etc.NetworkManager.NetworkManager.conf: 2012-11-25T12:30:38.408468
nmcli-dev:
 DEVICE TYPE STATE DBUS-PATH
 wlan0 802-11-wireless connected /org/freedesktop/NetworkManager/Devices/1
 eth0 802-3-ethernet unavailable /org/freedesktop/NetworkManager/Devices/0
nmcli-nm:
 RUNNING VERSION STATE NET-ENABLED WIFI-HARDWARE WIFI WWAN-HARDWARE WWAN
 running 0.9.6.0 connected enabled enabled enabled enabled enabled

[Pavel Šimerda (pavlix-a)]

Upstream bug report with comments:

https://bugzilla.gnome.org/show_bug.cgi?id=692279

[Launchpad Janitor (janitor)]

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

[Thiago Martins (martinx)]

Guys,

This BUG is still present on Ubuntu 14.04.1, look:

---
user@desk-1:~$ ip -6 route
2001:129X:2bX:Xfff::/64 dev wlan0 proto kernel metric 256 expires 85937sec
fe80::/64 dev wlan0 proto kernel metric 256
default via fe80::6666:b3ff:fe4b:20f4 dev wlan0 proto static metric 1 # WRONG!!
default via fe80::6666:b3ff:fe4b:20f4 dev wlan0 proto ra metric 1024 expires 1337sec
---

The first "default" line is definitely wrong. It remains there even after a disabled RA daemon (like in a H.A. for IPv6), which "breaks the IPv6 architecture for router redundancy - as OP said".

Trusty needs to be patched ASAP!

[Thiago Martins (martinx)]

This BUG is still present on Ubuntu 14.10 - upgraded today.

[Thiago Martins (martinx)]

It is unbelievable that this problem was already fixed in `gnome-bugs #692279` and still not fixed here in Ubuntu.

This is very, very annoying.

Please guys, do something about this.

Thanks in advance.

-
 Thiago

[Thiago Martins (martinx)]

Hey guys!

 This problem still exists on Ubuntu Vivid!

 Come on! Ubuntu Desktop is near useless on a network with IPv6 + SLAAC with Routers in H.A. When the main router dies, the slave router becomes active (radvd) but, all Ubuntu Desktops (Gnome / Unity) doesn't see the new IPv6 router. While Windows, Mac, Ubuntu Servers (without NM) and Enlightenment DE with Econnman are working as expected.

 Please, fix this! Maybe it is time to bring Network Manager 1.0 to Ubuntu.

 Right now, on my personal machine, I removed network-manager packages and I'm configuring my IPv6 network directly on /etc/network/interfaces, since NM is useless on an IPv6 + SLAAC network with routers in H.A..

 Also, my laptop have Econnman, from Enlightenment project. It works like a charm! But it doesn't have support for proxy settings, then, I'm stucked with manual config. :-/

Thanks,
Thiago

[nickchettle (ni0k)]

I too am seeing this bug but with a slightly different use-case. If a user swaps out their default router, no IPv6 traffic will pass because of the static route installed. I have to disconnect the interface in Ubuntu and then reconnect to clear the static. At that point, the new default-route learnt via RA's takes over.

It would be really great to get this one fixed. As IPv6 deployment starts to ramp up it is going to affect more and more people.

Thanks, Nick

[Thiago Martins (martinx)]

This is fixed on Xenial 16.04! YAY! :-D

[Suho Meso (kunalija)]

Hi Thiago,

how did you fix the issue?

On my 16.04 workstation i still have the issue.

2 Routers generate RAs, the routing table on the clients looks like:
default via fe80::xxxxxx dev enp0s25 proto static metric 100 pref medium

[leeA (leea4445)]

Hi
I also have this problem and for me it seems this bug is not realy resolved. Are there any more insights on this?

[Kenneth R. Crudup (kenny-panix)]

I believe I am affected by this issue as well. I have a Google WiFi device as a router, and everything works well for the first few days, with the link-local address used on the Google WiFi's RA used as the IPv6 default route.

After a couple of days however, the Google WiFi device changes its link-local address (for some reason) on the LAN subnet, and although an RA goes out with this new link-local address, NetworkManager still hangs onto the old default route (which is marked "static" as well) and as such I lose IPv6 connectivity to the outside world. I have to run "nmcli conn up Ethernet" to force NM to delete the old default route and use a the new one.

Also, if I manually "ip -6 replace default ..." leaving the line otherwise intact as it comes from NM, changing only "proto static" to "proto ra", as soon as the Google WiFi sends another RA, NM re-writes the default as "proto static"- yet does NOT update the actual "via" link-local address to the one the RA came in on.