SMTP over IPv6 : gmail classifying nearly all IPv6 mail as spam since 20140818

Philipp Kern phil at
Sun Aug 24 18:32:11 CEST 2014

On Sat, Aug 23, 2014 at 06:31:33PM +0000, Matthew Huff wrote:
> Sorry, but it hasn't happened yet. It isn't computationally infeasible, it's
> that the implementations on the RBLS haven't caught up. Currently the backend
> for the RBLS in many cases are based on DNS resolvers such as bind, etc,
> which doesn't have a mechanism to return values for subnets, so until the RBL
> users add new features, test and roll them out, currently there is very
> limited IPv6 address reputation systems. Until there are, many mail systems
> are relying instead on rDNS/SPF/DKIM/DMARC. It's not an unsolvable problem
> it's just that it hasn't been implemented.

Caching problems aside you can serve wildcards as long as the IP parts are

Kind regards
Philipp Kern

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