<div dir="ltr">I was under the impression that it wasn't so much about there being more IPv6 spam as much as tracking IPv6 reputation based on addresses was computationally infeasible.<div><br></div><div>If a spammer gets a hold of a /64, then the spammer can send 18 billion billion (~2^64) different email addresses, each coming from a different IP address. Never-mind that a spammer can go to a half-dozen tunnel brokers and get /48s for free.</div>
<div class="gmail_extra"><div><br></div>-- <br><div dir="ltr">Michael Chang</div><br><div class="gmail_quote">On Fri, Aug 22, 2014 at 8:18 PM, Brian E Carpenter <span dir="ltr"><<a href="mailto:brian.e.carpenter@gmail.com" target="_blank">brian.e.carpenter@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div>On 23/08/2014 11:16, 🔓Dan Wing wrote:<br>
> On Aug 22, 2014, at 7:42 AM, Matthew Huff <<a href="mailto:mhuff@ox.com" target="_blank">mhuff@ox.com</a>> wrote:<br>
><br>
>> Currently it is not feasible to do ipv6 reputation filtering. IPv4 reputation filtering is a big part of most anti-spam engines, so without it, SPF / DKIM of domain reputation is the best alternative.<br>
>><br>
>> BTW, we have had to remove all IPv6 from our mail gateways due to the large number of Exchange SBS with broken isatap/6to4 tunnels causing mail to blackhole.<br>
><br>
> MTU issue?<br>
<br>
</div>I can't speak for Teredo, but for 6to4 there is a whole list of<br>
possible issues ( <a href="http://tools.ietf.org/html/rfc6343" target="_blank">http://tools.ietf.org/html/rfc6343</a> ). PMTUD failure<br>
and/or MSS negotiation failure are on the list, and so is reverse<br>
DNS failure.<br>
<span><font color="#888888"><br>
Brian<br>
</font></span><div><div><br>
><br>
> -d<br>
><br>
><br>
>> These have been at small web based retailers which don't have hosted email. After the third incident, we yanked our IPv6 from our MX/gateways.<br>
>><br>
>><br>
>><br>
>> ----<br>
>> Matthew Huff | 1 Manhattanville Rd<br>
>> Director of Operations | Purchase, NY 10577<br>
>> OTA Management LLC | Phone: <a href="tel:914-460-4039" value="+19144604039" target="_blank">914-460-4039</a><br>
>><br>
>> -----Original Message-----<br>
>> From: ipv6-ops-bounces+mhuff=<a href="mailto:ox.com@lists.cluenet.de" target="_blank">ox.com@lists.cluenet.de</a> [mailto:<a href="mailto:ipv6-ops-bounces%2Bmhuff" target="_blank">ipv6-ops-bounces+mhuff</a>=<a href="mailto:ox.com@lists.cluenet.de" target="_blank">ox.com@lists.cluenet.de</a>] On Behalf Of Nick Hilliard<br>
>> Sent: Friday, August 22, 2014 10:25 AM<br>
>> To: Lorenzo Colitti; Laurent GUERBY<br>
>> Cc: IPv6 Ops list<br>
>> Subject: Re: SMTP over IPv6 : gmail classifying nearly all IPv6 mail as spam since 20140818<br>
>><br>
>> On 22/08/2014 15:16, Lorenzo Colitti wrote:<br>
>>> Are you following the "Additional guidelines for IPv6" section of<br>
>>> <a href="https://support.google.com/mail/answer/81126" target="_blank">https://support.google.com/mail/answer/81126</a> ?<br>
>> Lorenzo,<br>
>><br>
>> it looks like Google is trying to enforce SPF / DKIM on ipv6 connections<br>
>> where there is no similar requirement for ipv4. Is there a particular<br>
>> reason for this? It's causing a lot of breakage.<br>
>><br>
>> Nick<br>
>><br>
><br>
><br>
<br>
</div></div></blockquote></div><div dir="ltr"><br></div>
</div></div>