ARC – Authenticated Received Chain – is a way for email forwarders to mitigate the problems caused by users sending mail from domains with DMARC p=reject. It allows a forwarder to record the DKIM authentication as they receive a mail, then “tunnel” that authentication on to the final recipient. If the final recipient trusts the forwarder, then they can also trust the...
Google is disabling support for email sent using version 3 of SSL or using the RC4 cypher. They’re both very old – SSLv3 was obsoleted by TLS1.0 in 1999, and RC4 is nearly thirty years old and while it’s aged better than some cyphers there are multiple attacks against it and it’s been replaced with more recent cyphers almost everywhere. Google has more to say about it on...
Mail.ru is switching to p=reject. This means that you should special-case mail.ru wherever … Actually, no. Time to change that script. If you operate an ESP or develop mailing list software you should be checking whether the email address that is being used in the From: address of email you’re sending is in a domain that’s publishing p=reject (is a “rejective” email...
Zurb announced today version 2 of “Foundation for Email”, a full stack for designing content for responsive email. It looks rather nice, with features a modern web developer might look for when working on email content. It has many of the things you’d expect a web design stack to have. It support SASS for styling, includes browser sync for previewing content as it’s...
I talked on Monday about the SPF rule of ten and how it made it difficult for companies to use multiple services that send email on their behalf. Today I’m going to look at how to fix things, by shrinking bloated SPF records. This is mostly aimed at those services who send email on their customers behalf and ask their customers to include an SPF record as that’s the biggest pain...
Some mechanisms and modifiers (collectively, “terms”) cause DNS queries at the time of evaluation, and some do not. The following terms cause DNS queries: the “include”, “a”, “mx”, “ptr”, and “exists” mechanisms, and the “redirect” modifier. SPF implementations MUST limit the total number of those terms to 10...
“All mail clients suck. This one just sucks less.” Mutt is a commandline mail client that’s been in use and been actively developed for about two decades. It’s considered by many to be the most powerful mail client available, particularly for handling large volumes of email. It’s weaknesses include poor rich text handling and desktop integration for attachment...
An old blog post from 2013, that’s still relevant today. “Blocked for Bot-like Behavior” An ESP asked about this error message from Hotmail and what to do about it. “Bot-like” behaviour usually means the sending server is doing something that bots also do. It’s not always that they’re spamming, often it’s a technical issue. But the technical problems make the sending server look like a bot...
When you click on a link in your mail, where does it go? Are you sure? HTTP Redirects In most bulk mail sent the links in the mail aren’t the same as the page the recipients browser ends up at when they click on it. Instead, the link in the mail goes to a “click tracker” run by the ESP that records that that recipient clicked on this link in this email, then redirects the...
Using SSL TLS to protect data in transit and authenticate servers you contacted originally required specialized software, complex configuration and expensive and complicated to require certificates. The need for specialized software is long since gone. Pretty much every web server and mail server will support SSL out of the box. Basic server configuration is now pretty simple – give the...
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