DKIM and DomainKeys, Spam and Ham

I’ve been preaching “DKIM is great! DomainKeys is obsolete, get rid of it!” for several years now. I thought I’d take a look at my mailbox and see who was using authentication.
I’ve divided this into “Ham” and “Spam”. Spam is, well, all the spam I’ve received over the past couple of years. Ham is the non-spam mail in my inbox, whether personal, business, bulk or transactional. I’ve excluded most of the discussion mailing lists I’m on (not least because many of them consist of people in the email industry or are email standards development mailing lists, so have email authentication levels that are way outside the norm).

Spam and Ham

 
Most legitimate mail – between 50% and 70% – is authenticated using DKIM, but signing levels seem fairly steady, with maybe a slight upward trend. Very little spam is authenticated at all. DomainKeys usage is pretty low, and seems to be gradually declining.
The end result isn’t terribly surprising, but having hard numbers is mildly interesting.
 

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Do you have an abuse@ address?

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My usual complaints contain a plain text copy of the mail, including full headers and a short summary of the email address it was sent to. “This is an address that was part of a leak from…” or “This is an address scraped off my website. It’s been removed from the website since 2004” or “This address isn’t used to sign up for any mail.”
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It’s frustrating to watch an ESP post long blog posts about “best practices” and “effective delivery” and “not spamming” and yet not be able to actually stop their own customers from spamming. It’s not even that I necessarily want them to disconnect their spamming customers (although that would be nice) but suppressing the address that I’ve told them was a spamtrap seems trivial. And yet, a month after my first complaint and weeks after escalating to a personal contact, I’m still getting spam.
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Email filters are essential to protect us from scammers. Sometimes I forget this, and then I read about a grandmother getting swindled by a Nigerian scammer and ending up dead.
There are real consequences to poor filtering and there is real crime facilitated by email. It’s easy to forget this as we deal with the email that gets caught in filters when they shouldn’t.
Filters are one of the first lines of defense against online crime.
Not only does filtering stop crime, but they also keep email working. An unfiltered mail stream is an ugly, unreadable, unworkable mess.

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