Recent Posts

Deliverability Week

Deliverability Matters. Deliverability Week 2024.

Next week everyone will be talking Deliverability.

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SWAKS: Test your SMTP

We’ve mentioned SWAKS here a few times – but I always use it for delivering test mail directly to a recipient’s MX.

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DNS for white label authentication with SproutDNS

I wrote last year about using “stunt” nameservers for customer subdomain authentication – i.e. dynamically generating all the authentication records needed in DNS for each customer as needed.

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Deliverability Summit 2024

We just got back from Amsterdam a couple of days ago, after attending the Deliverability Summit.

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Anatomy of a Received header

When trying to find out why Something Went Wrong during delivery of an email we sometimes want to look at the route by which it was delivered.

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Looking back, looking forward

Six years ago today I wrote here “Spam isn’t going away“, talking about systemic problems at Google, Cloudflare and Amazon and in India.

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Errors in DKIM records

TXT Records

DKIM public keys live in DNS TXT records. A DNS TXT record contains strings of text, and each string is limited to be no more than 255 characters long.

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One-click unsubscribe

The worst thing about the yahoogle requirements has been their use of the term “one-click unsubscribe”. It’s an overloaded term that’s being used here to mean RFC 8058 in-app unsubscription. That’s a completely different thing to what one-click unsubscription has been used to mean for decades, often in the context of complying with legal requirements around unsubscription.

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Don’t trust Gmail’s Show Original

It’s not always easy to know what the actual headers and body of an email as sent look like. For a long time accepted wisdom was that you could send a copy to your gmail account, and use the Show Original menu option to, well, see the original message as raw text.

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