[lxc-users] LXD Bridged IPv6

Tue Apr 26 07:45:40 UTC 2016

Curious, the symptoms are almost consistent with when you're trying
to do routing within a single subnet (which means NDP packets won't
reach their destination and you need to either setup neighbor proxying
with `ip neighbor` per-container or setup an ndp proxy daemon (ndppd)),
yet your container did get successfully autoconfigured? Are you
running a router advertiser on your host (radvd, dnsmasq, ...) or are
the routes advertised by your provider? (If the latter is the case,
is eth0 attached to lxdbr0 or are you really only routing?)

The host's `ip a` and `ip -6 r` output would be useful (ifconfig
lacks bridge port information and instead contains lots of useless stuff).

(Obviously any relevant firewall configuration would also be useful)

You can also use `tcpdump` to try and track the NDP and ping packets,
see which part fails and where.

How does your IPv4 setup compare to this, and do you use proxy_arp
with IPv4?

> On April 25, 2016 at 2:30 PM Nick Falcone <nick at nfalcone.net> wrote:
> 
> 
> root at test9001:~# ip -6 r
> 2604:a880:0:1010::/64 dev eth0  proto kernel  metric 256  expires
> 3434sec pref medium
> fe80::/64 dev eth0  proto kernel  metric 256  pref medium
> default via fe80::684e:dcff:feae:fd61 dev eth0  proto ra  metric 1024 
> expires 1634sec hoplimit 64 pref medium
> 
> 
> root at test9001:~# default via fe80::1 dev eth0  metric 1024  pref medium
> 
> 
> after adding the route you suggested I still get:
> ip -6 route del default
> ip -6 route add default via fe80::1 dev eth0
> From 2604:a880:0:1010:216:3eff:fe87:ff20 icmp_seq=15 Destination
> unreachable: Address unreachable
> 
> On Mon, Apr 25, 2016, at 07:25 AM, Wojciech Arabczyk wrote:
> > What are your route settings in the container?
> > ip -6 route show
> > 
> > Have you tried adding the generic default route via:
> > ip -6 route add default via fe80::1 dev eth0
> > on the container itself?
> > 
> > On 25 April 2016 at 13:11, Nick Falcone <nick at nfalcone.net> wrote:
> > > In my sysctl.conf I have:
> > >
> > > net.ipv4.ip_forward=1
> > > net.ipv6.conf.all.forwarding=1
> > >
> > >
> > > and just to double check
> > >
> > > root at lxdtest:~# sysctl net.ipv4.ip_forward
> > > net.ipv4.ip_forward = 1
> > > root at lxdtest:~# sysctl net.ipv6.conf.all.forwarding
> > > net.ipv6.conf.all.forwarding = 1
> > >
> > > On Mon, Apr 25, 2016, at 03:44 AM, Wojciech Arabczyk wrote:
> > >> Are you sure, you have enabled ipv6 forwarding via sysctl?
> > >>
> > >> On 22 April 2016 at 18:10, Nick Falcone <nick at nfalcone.net> wrote:
> > >> > Hello
> > >> >
> > >> > I have been banging my head up against a wall for a few days now trying
> > >> > to get IPv6 to work across my bridged interface for my containers.
> > >> >
> > >> > I have tried different VPS and dedicated servers as well as versions of
> > >> > Ubuntu 14.04, 15.10, and 16.04 to get this working.  The latest test all
> > >> > this info is from an Ubuntu 16.04 with the included version of LXD.
> > >> >
> > >> > First I install and run lxd init, I configure the bridge like so.
> > >> >
> > >> > lxdbr0    Link encap:Ethernet  HWaddr fe:82:af:f0:5d:ce
> > >> >           inet addr:10.195.87.1  Bcast:0.0.0.0  Mask:255.255.255.0
> > >> >           inet6 addr: 2604:a880:0:1010::623:2/64 Scope:Global
> > >> >           inet6 addr: fe80::40c6:84ff:fe18:22fb/64 Scope:Link
> > >> >           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
> > >> >           RX packets:294 errors:0 dropped:0 overruns:0 frame:0
> > >> >           TX packets:18 errors:0 dropped:0 overruns:0 carrier:0
> > >> >           collisions:0 txqueuelen:1000
> > >> >           RX bytes:21612 (21.6 KB)  TX bytes:2127 (2.1 KB)
> > >> >
> > >> > This is my host information too
> > >> >
> > >> > eth0      Link encap:Ethernet  HWaddr 04:01:d4:50:c4:01
> > >> >           inet addr:162.243.200.170  Bcast:162.243.200.255
> > >> >           Mask:255.255.255.0
> > >> >           inet6 addr: fe80::601:d4ff:fe50:c401/64 Scope:Link
> > >> >           inet6 addr: 2604:a880:0:1010::623:1/64 Scope:Global
> > >> >           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
> > >> >           RX packets:76258 errors:0 dropped:0 overruns:0 frame:0
> > >> >           TX packets:8187 errors:0 dropped:0 overruns:0 carrier:0
> > >> >           collisions:0 txqueuelen:1000
> > >> >           RX bytes:111074998 (111.0 MB)  TX bytes:1230729 (1.2 MB)
> > >> >
> > >> > I launch and enter the first container it has this info:
> > >> >
> > >> > eth0      Link encap:Ethernet  HWaddr 00:16:3e:87:ff:20
> > >> >           inet addr:10.195.87.69  Bcast:10.195.87.255
> > >> >           Mask:255.255.255.0
> > >> >           inet6 addr: 2604:a880:0:1010:216:3eff:fe87:ff20/64
> > >> >           Scope:Global
> > >> >           inet6 addr: fe80::216:3eff:fe87:ff20/64 Scope:Link
> > >> >           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
> > >> >           RX packets:20 errors:0 dropped:0 overruns:0 frame:0
> > >> >           TX packets:294 errors:0 dropped:0 overruns:0 carrier:0
> > >> >           collisions:0 txqueuelen:1000
> > >> >           RX bytes:2175 (2.1 KB)  TX bytes:25728 (25.7 KB)
> > >> >
> > >> > so here I can see slaac is successful, but I cannot ping6
> > >> > 2604:a880:0:1010::623:1 (the host ipv6), I cannot ping google's public
> > >> > dns ipv6 either.  I CAN successfully ping6 2604:a880:0:1010::623:2 my
> > >> > bridge public IPv6.
> > >> >
> > >> > Seems like a routing issue, so on the host I add:
> > >> > ip -6 route add 2604:a880:0:1010:216:3eff:fe87:ff20 dev lxdbr0
> > >> >
> > >> >
> > >> > Still not able to ping6 out.  As a side note IPv4 works great.
> > >> >
> > >> > Am I missing something here? I cannot seem to find a lot of docs on this
> > >> > small part.  I thought to look at the demo containers on
> > >> > https://linuxcontainers.org/lxd/try-it/ but am unable to ping6 out on
> > >> > those, is this just a limitation?
> > >> >
> > >> > Thanks for any help in advance, would really like to use lxd for a
> > >> > project.  Also I do not care to redact these real IPs, they belong to a
> > >> > box only used for getting this working then will be destroyed.
> > >> > _______________________________________________
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