is gmail strongly penalizing IPv6 senders?

[staticsafe]

On Thu, May 30, 2013 at 04:46:02PM +0200, 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.)
> 
> -- 
> ciao,
> Marco

Gmail is outright rejecting my MX over v6, something about "bulk mail"
which makes no sense as this is a personal e-mail server. I've worked
around the issue by telling Postfix to prefer ipv4 for sending.
-- 
staticsafe
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