Re: [exim] Gmail's new 'suspicious sender' flag

On 6 Jul 2011, at 13:56, Jan Ingvoldstad wrote:

> On Wed, Jul 6, 2011 at 14:40, Ian Eiloart <iane@???> wrote:
>
>> Since few message paths involve both forwarding AND a mailing list,
>
>
> How few is "few", do you have any statistics?

No, I'm afraid I don't. But, forwarding is generally used to pass on mail that's being delivered to an incorrect address. If it's a mailing list that you're subscribed to, then you should be able to fix that.



> Are they few enough to warrant broken email?
>
> Even the difference between a mailing list and a forwarding is tenuous at
> best.

Well, I'll define it - for the purpose of this discussion.

Forwarders do not rewrite sender addresses, but neither do they modify message data. That's why forwarding breaks SPF but not DKIM. They include "exploders" that forward to several addresses.

Mailing lists DO modify sender addresses (thus avoiding concerns about SPF), but often modify message data, thus breaking DKIM signatures. Mailing list operators are advised to sign outbound email so that recipients have a signature that will verify. Since the list operator can be regarded as the message originator, that's an entirely appropriate action.

> It is increasingly popular with vanity domains, with a simplistic mail
> forwarding service, as exemplified by an earlier post I made. I have a few
> such domains myself, with such simplistic forwarding, and I have
> list-specific addresses subscribed to dozens of mailing lists.
>
> I'm not happy when I don't get email because someone fibbled their SPF.
>

And I'm not happy when 50% of my email can't be checked against a reputation service, because I have no idea who it's from! All this talk of breaking various edge cases in an incredibly broken system is missing the big picture.

--
Ian Eiloart
Postmaster, University of Sussex
+44 (0) 1273 87-3148