Re: [Xen-devel] [xen-4.0-testing test] 2045: regressions - FAIL

[Ian Campbell <Ian.Campbell@xxxxxxxxxxxxx>]

On Tue, 2010-08-31 at 15:35 +0100, Ian Jackson wrote:
> 
> > Even with the fix in place the gratuitous ARP behaviour is disabled
> by
> > default so you need to enable the net.ipv4.conf.<dev>.arp_notify
> sysctl
> > for any device you want to send the notifications. When I was
> testing I
> > did this by adding
> >         net.ipv4.conf.default.arp_notify = 1
> > to /etc/sysctl.conf and that seemed to do the trick.
> 
> I think this is a bug.  I think the default should be for something to
> send this gratuitous arp and the most logical answer in the PV or
> PV-on-HVM case is the domU.

This is the upstream default, not something we control directly from
netfront etc.

> However: all of this doesn't apply to the test network used for these
> tests.  There is a daemon on that network which sends broadcast ARP
> who-has packets for every IP address at very short intervals (5s or
> so) and the reply will cause the switches to update their ideas of
> MAC<->port mapping.

Is this daemon specifically working around this issue or is there some
other purpose which I can't quite think of?

Ian.


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