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Tag: dmarc

DMARC=BestGuessPass

Looking at the headers within the mail received with my Office365 domain I see dmarc=bestguesspass.  BestGuessPass?  That’s a new. A few days after seeing dmarc=bestguesspass, Terry Zink at Microsoft posted an explanation. Exchange Online Protection, the filtering system for Office365, is analyzing the authentication of incoming emails and if the domain is not publishing a […]

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Authentication and Repudiation

Email Authentication lets you demonstrate that you sent a particular email. Email Repudiation is a claim that you didn’t send a particular email.   SPF is only for email authentication1 DKIM is only for email authentication DMARC is only for email repudiation   1 SPF was originally intended to provide repudiation, but it didn’t work reliably enough to […]

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Ransomware email protected by DMARC

Virus bulletin has an interesting post about DMARC and how some criminals are protecting their emails with DMARC.

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Salesforce SPF and now DKIM support

Salesforce has published a SPF record for sending emails from Salesforce for years and with the Spring ’15 release, they will provide the option to sign with DKIM. The SPF record is straight forward, include:_spf.salesforce.com which includes _spf.google.com, _spfblock.salesforce.com, several IP address blocks, mx, and ends with a SoftFail ~all. Salesforce Knowledge Article Number: 000006347 […]

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Email Authentication in a nutshell

There are 3 types of authentication currently in use for email. DKIM SPF DMARC The different strategies do different things with email. DKIM cryptographically signs emails, preventing changes in transit, and designates a “responsible domain” through the d= value in the signature. SPF compare the sending IP and the envelope from (also known as the bounce string, return […]

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January 2015 – The Month in Email

It’s February already! January went fast, right? At WttW, we are gearing up for MAAWG SF later this month — will we see you there? We started the year with a set of predictions about email. Mostly we think email will continue to be great at some things and not-so-great at other things, and we’ll […]

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Office365 checking DMARC on the inbound

According to a recent blog post, Office365 is starting to evaluate incoming messages for DMARC. I talked a little bit about DMARC in April when Yahoo started publishing a p=reject message. DMARC stands for Domain-based Message Authentication, Reporting and Conformance. What DMARC does is allow domain owners to publish policy statements in DNS telling receiver domains […]

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Email predictions for 2015

Welcome to a whole new year. It seems the changing of the year brings out people predicting what they think will happen in the coming year. It’s something I’ve indulged in a couple times over my years of blogging, but email is a generally stable technology and it’s kind of boring to predict a new […]

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Spam, Phish or Malware?

Some mornings I check mail from my phone. This showed up this morning. My first thought was “oh, no, Pizza Hut is spamming, wonder who sold them my address.” Then I remembered that iOS is horrible and won’t show you anything other than the Friendly From and maybe it was some weird phishing scheme. When […]

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September 2014: The Month in Email

September was another busy month for us, but Steve stepped up and wrote a number of really interesting posts on email history, cryptography, and current technical issues in the email landscape. We started the month with a look at the various RFCs that served as the technical specifications for developing message transfer protocols in the 1970s. […]

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