current usage of AAAA implicit MX?

Tim Chown tjc at
Tue Apr 15 16:01:53 CEST 2008

On Tue, Apr 15, 2008 at 11:09:17AM +0100, David Malone wrote:
> On Tue, Apr 15, 2008 at 12:12:06PM +0930, Michael Taht wrote:
> > I implemented three ipv6/ipv4 dual stack email servers a while back. The
> > ONLY connections I've ever seen on it from the public internet have been
> > IPv4, except from my own machines.
> Excluding locals, I see about 100 different hosts doing incomming
> IPv6 SMTP each month for about 14K smtp sessions. Now, I probably
> see about 1000000 different IPv4, but I suspect alot of those are
> bots who try a couple of sessions and move on, as I only see maybe
> 5000000 smtp sessions in total.

So I just ran nfsen on our last month of IPv6 traffic and see there
is around 40,000 flows on our MXes for around 200MB of data, and
around 400 different flow endpoints, of which 24 are 6to4 prefixes.

A small proportion of internal flows may be included in those numbers,
but around 1000 IPv6 transport mails in per day wouldn't be far out.

In comparison I believe we have around 500K IPv4 SMTP connections inbound 
per day, of which less than 20% are deemed 'wanted' mail.


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