[AusNOG] IPv6 - test ... Testing your dual stacked mail system is moving mail on v6 - helpful resources.

Don Gould don at bowenvale.co.nz
Fri Mar 8 13:42:33 EST 2013

On 8/03/2013 3:37 p.m., Jeremy Visser wrote:
> On 08/03/13 13:27, Don Gould wrote:
>> sorry guys, just ignore, I'm just running a tcp dump as requested to see
>> if we can figure why my traffic isn't heading via v6.
> To save further noise, five minutes ago I set up
> blackhole at sunriseroad.net (dual-stack) and
> blackhole at ipv6.sunriseroad.net (IPv6-only) that you can use to test.

Can you make that do an out of office bounce back?  That would be more 
helpful to see what's coming back in the headers.

> My /etc/aliases contains:
>    blackhole: "|/bin/true"
> Feel free to spam that address anyone setting up IPv6 mail. Just tested
> with work's Exchange 2010 server and it appears to work fine.
> Interestingly enough, despite our Exchange being dual-stack, it always
> prefers IPv4. Wonder if that is configurable.

Interesting, so what we're learning here is that these numbers we're 
seeing about v6 traffic are a bit meaningless and no indication of demand.

Guys have dual stacked stuff but they're just not moving any traffic on 
it.  Sort of need to fix that for obvious reasons.


Don Gould
31 Acheson Ave
Christchurch, New Zealand
Ph: + 64 3 348 7235
Mobile: + 64 21 114 0699

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