Recent Posts

Laposte.net will be requiring all email be authenticated

Starting on September 9th laposte.net will begin requiring email to have valid, aligned authentication. Mail that isn’t authenticated will start to be delivered to the spam folder or rejected at delivery time.

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Yahoo's mailboxes are full

552 5.2.2 This message could not be delivered because the recipient’s mailbox is full. Please try again later or contact the recipient directly. See https://senders.yahooinc.com/smtp-error-codes#mailbox-full for more information

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Deliverability rules

Hot Take:

Anyone who has to know exactly what the rules are for inbox delivery is trying to figure out how close they can get to violating the rules without negative consequences. Senders that comply with the spirit of the rules don’t care what the specifics of the rules are.

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Message-ID Syntax

Our friends in the Email Geeks slack have recently started seeing sporadic rejections due to invalid Message-ID headers.

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Don't make your DNS TTLs too short

DNS is a complex, distributed database built on top of an unreliable network that spans the world.

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Gmail says your unsubscribe "Needs work"

Google postmaster tools dashboard with a “Needs work” message for Honour unsubscribe

Needs work?

We’ve written about RFC 8058 “one-click” unsubscribe and how it’s part of the requirements for bulk senders wanting to deliver mail to the major consumer mailbox providers.

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About that cold email

Over the years I’ve made the decision to stop working with certain types of senders. Most recently it’s been the decision to not work with companies sending cold email. I even wrote a blog post back in 2018 about my frustration with clients who were upset their cold email was going to the spam folder. That was the beginning of the end for cold emailers as clients. I did continue to try and work with those senders, but they were incredibly frustrating engagements. I’d offer all my best practices, even try and work out how they could continue to use their purchased lists. They simply didn’t listen, they just didn’t want to hear that deliverability isn’t just about numbers and they couldn’t metric their way into the inbox. What they really wanted was me to tell them the One Weird Trick that would get their mail into the inbox.

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You can't DKIM sign a cabbage

The DKIM specification and implementations of DKIM signing and validation code make some unstated assumptions about the environment they’re running in.

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The Challenges of B2B deliverability

Tomorrow Laura will be giving a webinar as part of the MarketingProfs Summer series. She’ll be speaking specifically about Rising to the Challenge of B2B Deliverability. This talk discusses the fundamental differences between business and consumer mailboxes and how we can’t just apply consumer mailbox deliverability advice to a business environment.

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SWAKS on macOS

SWAKS is my favorite SMTP debugging tool.

A new SMTP server I’m building loses pipelining synchronization when connecting via TLS, and I’m sure the bug will be simple to spot if I can send some test messages in to it and watch the sequence of commands. SWAKS is perfect for that.

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