is gmail strongly penalizing IPv6 senders?

[Jeroen Massar]

On 2013-05-30 07:46, Marco d'Itri wrote:
> I have noticed in the last few days that mail sent to gmail from a 
> significant number of our servers (both shared hosting / mail relays and 
> dedicated servers of our customers) with IPv6 connectivity is delivered 
> to the spam folder.
> If there has been spamming activity (as a result of some security 
> incident, I am not an ESP) from some of these servers then it is not 
> recent.
> The reputation problem is tied to the IP address, because after adding 
> a new one in the same /64 mail is delivered to the inbox.
> 
> 
> (OTOH, recently I have received significant complaints from customers 
> about gmail rejecting connections or delivering to the spam folder even 
> long after a security incident, so this may be not specific to IPv6.)

Various people have been reporting related events:
  http://www.sixxs.net/forum/?msg=general-9241166

Seems something in the Big G classifies IPv6 as 'bad' quite quickly for
some magic reason.

Greets,
 Jeroen