Re: FAQ on linux-kvm.org has broken link

[folkert <folkert@vanheusden.com>]

> > The link at:
> > http://www.linux-kvm.org/page/FAQ#My_guest_network_is_stuck_what_should_I_do.3F
> > pointing to:
> > http://qemu-buch.de/cgi-bin/moin.cgi/QemuNetwork
> > is broken: it gives a "Internal server error" message.
> > 
> > Please someone point me to the correct location as I'm struggeling with
> > a VM losing connectivity all the time.
> 
> Hi Folkert,
> I have updated the wiki to point to
> http://qemu-project.org/Documentation/Networking.  The original link
> seems to be down.

Thanks!

> If you keep losing network connectivity you may have a MAC or IP address
> conflict.  The symptom is that network traffic is intermittent - for
> example, ping might work but a full TCP connection does not.

Well it seems that it does receive some traffic (mostly arp) but it
can't definately do any outgoing traffic at all. No ping, and all tcp
sessions stall too.

For now I created a "way around it" using an UMTS stick, so hopefully I
can now fix it (reboot the vm) when I'm not at the office.
I'll verify the mac addresses when it happens again.

I have a suspicion that it happens less frequently if I leave tcpdump
running on the interface in the guest. I've now stopped it.

> This happens when two guests are configured with identical MAC or IP
> addresses on the same bridge or subnet.  They will "fight" over the MAC
> or IP address and you will not be able to reliably communicate with
> those guests.

If that is the case, the something must change this later on? Because it
happens occasionally - sometimes in 5 minutes, sometimes in days. And no
new guests are started on that server. It has 3 guests that stay on.

> If you let libvirt set up networking for you all should be fine.  If you
> run qemu manually or customized the domain XML, then it's possible you
> have a misconfiguration.  Feel free to post the details so someone can
> help you.

Everything is setup by libvirt. Great software by the way!


Folkert van Heusden

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