IPv6 breakage in NetworkManager

[Dan Irwin]

Hi all,

Seeing significant issues with IPv6. After some time, IPv6 completely seems
to stop working. IPv4 is unaffected.

Re-connecting to wifi seems to restore IPv6 connectivity.

However, various things (ssh, firefox) stop working completely. Open ssh
sessions "freeze". Web page requests time out.

At the same time, I can access IPv6 resources from other machines which do
not run NetworkManager.

Next time this occurs, I hope to have some time to diagnose this problem
further. In the meantime, is anyone else seeing such breaking wrt IPv6?

Something to note, I run numerous servers with IPv6, both physical and
virtual. These servers run CentOS; None run NetworkManager, and all have
working IPv6 connectivity.

Cheers,

Dan

[Dan Irwin]

Hi Wolfgang,

I'm not using dhclient6, or dhcpv6 at all on the subnets I connect to.
Checking my system I don't see dhclient6 running. Sounds like a similar
problem though.

I might try the updated policy package mentioned in your bz - but only if
the changelog seems like it might help.

Thanks


On Thu, Jan 23, 2014 at 10:07 AM, Wolfgang S. Rupprecht <
wolfgang.rupprecht(a)gmail.com&gt; wrote:

>  Dan Irwin <rummymobile(a)gmail.com&gt; writes:
>  > Seeing significant issues with IPv6. After some time, IPv6 completely
>  > seems to stop working. IPv4 is unaffected.
>
>  I'm seeing an IPv6 breakage in NetworkManager/dhclient6 too.  At first
>  it looked like an Selinux problem (there was an avc), but fixing that
>  didn't stop the problem with NM not getting a working IPv6 address via
>  dhclient6.  BZ#1055226 https://bugzilla.redhat.com/show_bug.cgi?id=1055226
>
>  > Re-connecting to wifi seems to restore IPv6 connectivity.
>
>  Mine is via an ethernet connection to my cable modem which connects to
>  Comcast.  I can do a "systemctl restart NetworkManager" in order to get
>  an ipv6 address.
>
>  -wolfgang
>  --
>  users mailing list
>  users(a)lists.fedoraproject.org
>  To unsubscribe or change subscription options:
>  https://admin.fedoraproject.org/mailman/listinfo/users
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>

[Dan Irwin]

I have had some success in identifying the root cause of this. Today, IPv6
broke again, and I had some spare time to debug it.

It seems as though NetworkManager is setting up an IPv6 default route via
em1, even though I had em1 disabled.

Earlier, I had two default routes. One via em1, another via wlp2s0 (aka
wlan0):

default via fe80::d267:e5ff:feb5:235b dev wlp2s0  proto static  metric 1024
default via fe80::d267:e5ff:feb5:235b dev em1  proto ra  metric 1024
expires 593sec

One appears to be static, the other is received via ra on the disabled
interface.

I can only imagine this means my default route in IPv6 land has been
switching between the two interfaces. To me, this explains the dropped ssh
sessions, web browsing timeouts, and other flaky  behaviour which I am
attributing to loss of IPv6 DNS packages.

So, NetworkManager bug or kernel bug?

I can only assume NetworkManager is responsible for this.

Cheers




On Thu, Jan 23, 2014 at 1:29 PM, Dan Irwin <rummymobile(a)gmail.com&gt; wrote:

>  Hi Wolfgang,
>
>  I'm not using dhclient6, or dhcpv6 at all on the subnets I connect to.
>  Checking my system I don't see dhclient6 running. Sounds like a similar
>  problem though.
>
>  I might try the updated policy package mentioned in your bz - but only if
>  the changelog seems like it might help.
>
>  Thanks
>
>
>  On Thu, Jan 23, 2014 at 10:07 AM, Wolfgang S. Rupprecht <
>  wolfgang.rupprecht(a)gmail.com&gt; wrote:
>
> >
> > Dan Irwin <rummymobile(a)gmail.com&gt; writes:
> > > Seeing significant issues with IPv6. After some time, IPv6 completely
> > > seems to stop working. IPv4 is unaffected.
> >
> > I'm seeing an IPv6 breakage in NetworkManager/dhclient6 too.  At first
> > it looked like an Selinux problem (there was an avc), but fixing that
> > didn't stop the problem with NM not getting a working IPv6 address via
> > dhclient6.  BZ#1055226
> > https://bugzilla.redhat.com/show_bug.cgi?id=1055226
> >
> > > Re-connecting to wifi seems to restore IPv6 connectivity.
> >
> > Mine is via an ethernet connection to my cable modem which connects to
> > Comcast.  I can do a "systemctl restart NetworkManager" in order to get
> > an ipv6 address.
> >
> > -wolfgang
> > --
> > users mailing list
> > users(a)lists.fedoraproject.org
> > To unsubscribe or change subscription options:
> > https://admin.fedoraproject.org/mailman/listinfo/users
> > Fedora Code of Conduct: http://fedoraproject.org/code-of-conduct
> > Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
> > Have a question? Ask away: http://ask.fedoraproject.org
> >
>
>

[Wolfgang S. Rupprecht]

Dan Irwin <rummymobile(a)gmail.com&gt; writes:
>  Seeing significant issues with IPv6. After some time, IPv6
> completely
>  seems to stop working. IPv4 is unaffected. 
I'm seeing an IPv6 breakage in NetworkManager/dhclient6 too.  At first
it looked like an Selinux problem (there was an avc), but fixing that
didn't stop the problem with NM not getting a working IPv6 address via
dhclient6.  BZ#1055226 https://bugzilla.redhat.com/show_bug.cgi?id=1055226

>  Re-connecting to wifi seems to restore IPv6 connectivity. 
Mine is via an ethernet connection to my cable modem which connects to
Comcast.  I can do a "systemctl restart NetworkManager" in order to get
an ipv6 address.

-wolfgang

[Juan Orti Alcaine]

I have no problems with latest NetworkManager and IPv6 (configured as
static address)

2014/1/22 Dan Irwin <rummymobile(a)gmail.com&gt;:
>  Hi all,
>
>  Seeing significant issues with IPv6. After some time, IPv6 completely seems
>  to stop working. IPv4 is unaffected.
>
>  Re-connecting to wifi seems to restore IPv6 connectivity.
>
>  However, various things (ssh, firefox) stop working completely. Open ssh
>  sessions "freeze". Web page requests time out.
>
>  At the same time, I can access IPv6 resources from other machines which do
>  not run NetworkManager.
>
>  Next time this occurs, I hope to have some time to diagnose this problem
>  further. In the meantime, is anyone else seeing such breaking wrt IPv6?
>
>  Something to note, I run numerous servers with IPv6, both physical and
>  virtual. These servers run CentOS; None run NetworkManager, and all have
>  working IPv6 connectivity.
>
>  Cheers,
>
>  Dan
>
>  --
>  users mailing list
>  users(a)lists.fedoraproject.org
>  To unsubscribe or change subscription options:
>  https://admin.fedoraproject.org/mailman/listinfo/users
>  Fedora Code of Conduct: http://fedoraproject.org/code-of-conduct
>  Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
>  Have a question? Ask away: http://ask.fedoraproject.org
>  


-- 
Juan Orti
GPG Key: DEEBD08B - http://jorti.fedorapeople.org/pubkey.asc
Blog: https://apuntesderoot.wordpress.com/

[fedora]

Ever checked MTU? I had to go down to 1450 on the workstation  On the 
IPv6 router it is 1480.

suomi

On 2014-01-22 03:14, Dan Irwin wrote:
>  Hi all,
>
>  Seeing significant issues with IPv6. After some time, IPv6 completely
>  seems to stop working. IPv4 is unaffected.
>
>  Re-connecting to wifi seems to restore IPv6 connectivity.
>
>  However, various things (ssh, firefox) stop working completely. Open ssh
>  sessions "freeze". Web page requests time out.
>
>  At the same time, I can access IPv6 resources from other machines which
>  do not run NetworkManager.
>
>  Next time this occurs, I hope to have some time to diagnose this problem
>  further. In the meantime, is anyone else seeing such breaking wrt IPv6?
>
>  Something to note, I run numerous servers with IPv6, both physical and
>  virtual. These servers run CentOS; None run NetworkManager, and all have
>  working IPv6 connectivity.
>
>  Cheers,
>
>  Dan
>
>

[Tim]

Allegedly, on or about 22 January 2014, Dan Irwin sent:
>  Seeing significant issues with IPv6. After some time, IPv6
> completely
>  seems to stop working. IPv4 is unaffected.  
Check the mailing list archives, I seem to recall a similar situation
being described not that long ago.

-- 
[tim@localhost ~]$ uname -rsvp
Linux 3.9.10-100.fc17.x86_64 #1 SMP Sun Jul 14 01:31:27 UTC 2013 x86_64

All mail to my mailbox is automatically deleted, there is no point
trying to privately email me, I will only read messages posted to the
public lists.

George Orwell's '1984' was supposed to be a warning against tyranny, not
a set of instructions for supposedly democratic governments.