Email Authentication: SPF, DKIM, and DMARC Best Practices

Laposte.net tightens its requirements for email authentication

On Friday, August 22, in a message shared by Simon Bressier, Postmaster of Laposte.net, the mail provider announced a major shift in its deliverability and anti-spam policy starting in September 2025. The French webmail confirmed that email authentication standards (SPF, DKIM, and DMARC) will no longer be optional. Until now, some emails without authentication protocols […]

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Categories: Authentication, DMARC, Providers

Outlook Deliverability: A Silent Shift with Serious Consequences

Starting on June 17th, 2025 at 11:10 UTC, multiple high-volume senders – particularly in France – began experiencing a sudden surge in DKIM failures on emails sent to Microsoft domains (Outlook, Hotmail, etc.). These bounces occurred even though SPF and DMARC were properly configured. UPDATE – July, 10 2025 Since the original publication of this […]

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Categories: Authentication, Deliverability, Providers

Explore Postmastery’s New YouTube Channel Featuring Highlights from the Postmastery Day 2024 & EMAS.

We are pretty excited to announce the launch of Postmastery’s brand new YouTube channel, what we hope will be a hub for insightful and engaging content on email deliverability. Our first uploads feature sessions from the very first Postmastery Day at the Deliverability Summit, held at The Rosarium in Amsterdam on April 11, 2024. This […]

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Categories: Authentication, General

All the bounce we cannot see: A Deferral story

When we work in email deliverability, we constantly hear about the processing of bounces, sometimes about blocking bounces and more often about suppressing bounces… In short, as you will have understood, processing bounces is the absolute prerequisite to email deliverability … But then, what about Deferrals… Should we process them? And if yes, how? What […]

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Categories: Authentication, Deliverability, Deliverability

Google & Yahoo’s February Bulk Email Policies: A Guide to Compliance

On October 3rd 2023, Google and Yahoo introduced new requirements to fight spam! This is a major change for the email industry, while, for the first time, two of the biggest Mailbox Providers announced commonly that they will apply the same restrictions to bulk senders. Who is concerned about it? For Gmail personal accounts (Gmail.com […]

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Categories: Authentication, Deliverability, General

Making the Choice: On-Prem or ESPs?

In June of this year, we were in Prague as one of the proud sponsors of the Deliverability Summit. We also took part in a great panel discussion Expert Advice from Alice Cornell, Steve Tuck of Halon, Matthew Grove of Mailchimp and our own Maarten Oelering. The discussion focussed on owning your email infrastructure. https://vimeo.com/845510055/4570b89de8? […]

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Categories: Authentication, Deliverability, General

Improve Email Delivery with PowerMTA’s Defer-Job Setting

Email delivery is a critical aspect of any business’s communication strategy. However, maintaining a good reputation for your email delivery IP can be a challenge, especially when using a shared IP with multiple customers. In such a scenario, the actions of one customer with a low reputation can adversely affect the entire queue, causing delays […]

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Categories: Authentication, Deliverability, General, PowerMTA

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