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Tag: Authentication

Cost of authentication

At the end of last year, Steve wrote a post about the different types of authentication. I thought I’d build on that and write about the costs associated with each type. While I know a lot of my readers are actually on the sending side, I’m also going to talk about the costs associated with […]

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Authentication

Some notes on some of the different protocols used for authentication and authentication-adjacent things in email. Some of this is oral history, and some of it may be contradicted by later or more public historical revision. SPF Associates an email with a domain that takes responsibility for it. Originally Sender Permitted From, now Sender Policy […]

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Microsoft and SPF

Many deliverability folks stopped recommending publishing SPF records for the 5322.from address to get delivery to Microsoft. I even remember Microsoft saying they were stopping doing SenderID style checking. A discussion on the emailgeeks slack channel has me rethinking that. It started out with one participant asking if other folks were seeing delivery improvement at […]

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Why is DMARC failing?

Multiple times over the last few weeks folks have posted a screenshot of Google Postmaster tools showing some percentage of mail failing DMARC. They then ask why DMARC is failing. Thanks to how DMARC was designed, they don’t need to ask anyone this, they have all the data they need to work this out themselves. […]

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Should you publish a DMARC policy statement?

DMARC is a protocol that makes it very, very simple to shoot yourself in the foot. Setup is tricky and if you don’t get it exactly right you risk creating deliverability problems. The vast majority of companies SHOULD NOT publish a DMARC policy with p=reject or p=quarantine for their existing domains. DMARC policy statements are, […]

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Null sender address

A question came up on the email geeks slack channel about empty from addresses. I asked if they meant the 5321 or 5322 from address which prompted a question about if you could even have a null 5321 from. Yes, you can and it’s commonly used for some types of email. 5321.from is the bounce […]

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DMARC doesn’t fix phishing

Over the last few weeks I’ve had a lot of discussions with folks about DMARC and the very slow adoption. A big upsurge and multiple Facebook discussions were triggered by the ZDNet article DMARCs abysmal adoption explains why email spoofing is still a thing. There are a lot of reasons DMARC’s adoption has been slow, […]

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d= for data

A few ISPs use the d= value in the DKIM signature as a way to provide FBL and reputation data to senders. This has some good bits, in that senders can get FBLs and other information regardless of the IP address they’re using and whether or not they have sole access to it. There are […]

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Delivery is not dependent on authentication

All too often folks come to me with delivery problems and lead off with all of the things they’ve done to send mail right. They assure me they’re using SPF and DKIM and DMARC and they can’t understand why things are bad. There is this pervasive belief that if you do all the technical things […]

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AMP and Gmail

Yesterday,Gmail announced they’re rolling out AMP support in their web client, with support for mobil coming soon. AMP allows a more web page experience in email. Things that would previously have required clicking through to a separate web page, can now be done directly within the message. According to the announcement, this feature is only […]

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