Word to the Wise
Just a very, very short post with links to the Yahoo and Google requirements FAQs. Given I can’t ever remember them I’m guessing lots of y’all can’t either. Yahoo: https://senders.yahooinc.com/best-practices/ Google: https://support.google.com/a/answer/14229414
On January 9th at 6pm GMT, 1pm EST and 9am PST I’ll be speaking with Nout Boctor-Smith of Nine Lives Digital about the new Yahoo and Google technical requirements. In this webinar you’ll: Learn more about what these new email sender guidelines entail and how they differ from the status quo Understand why you’re being asked to do things that were previously handled by your ESP (email service provider) Discover what adjustments you can make now to ensure your emails reach their intended inboxes in 2024 We know folks have a lot of questions about these changes and how to comply with them, so we’ve made sure to leave time for them. I’m so looking forward to this opportunity and I hope you can join us! Reserve Your Space!
Happy 2024, everyone! We’ve released a shiny new tool to let folks self-check a lot of common questions we see about email requirements. Go to AboutMy.email and send an email to the email address it gives you. Once it receives that email it will go through it and do many of the basic checks we’d usually do to check the technical health of a client’s email1 and displays a detailed report of what it finds. Details it reports on include SPF DKIM DMARC BIMI, including details about the certificate and image What IP address it was sent from, and whether it has valid DNS The size of the mail as sent (no more arguments about Gmail clipping size) The SMTP session as it was delivered The raw payload of the mail as delivered Checks for line length, non-ascii characters, non-CRLF line endings Headers, both pretty (including RFC 2047 decoded) and
Meanwhile… I apparently gave chess.com an email address in 2007 – probably due to a client engagement? I don’t know. I unsubscribed from their mail at some point as there has only been one email from them between 2010 and 2021. Maybe this time they’ll actually unsubscribe me.
Since I wrote about it last month the requirements for bulk senders to Yahoo and Google have changed a little. The big change is that bulk senders need to authenticate with both SPF and DKIM, rather than SPF or DKIM. Only one of those has to align with the 822 From: header.
Email supports TLS (Transport Layer Security), what we used to call SSL. Unlike the web, which split it’s TLS support off into a completely different protocol – https, listening on port 443 vs http listening on port 80 – SMTP implements it inside it’s non-encrypted protocol. A mailserver advertises that it supports this by having the word “STARTTLS” in the banner it sends after you connect to it. Before you do much else you send the command “STARTTLS”. At this point the tcp connection to the mailserver stops speaking SMTP and is ready for the complex binary dance that is a TLS handshake. Once the negotiation of protocols and ciphers and session tokens is done SMTP comes back. It looks just like it did before, but now it’s all being tunneled over a secure, encrypted TLS session. Sometimes you want to find out a few more details about how a
On Tuesday I wrote about using DNS wildcards to implement customer-specific subdomains for email authentication. As I said then, that approach isn’t perfect. You’d much prefer to have per-customer domain authentication, where each customer has their own DKIM d= and ideally their own SPF records, rather than having all customers sharing those records and relying on loose DMARC alignment to have them to work with a per-customer subdomain in the 5322 From: header. But doing that with DNS wildcards would have some odd side effects, such as TXT records appearing where they weren’t expected, in ways that could trigger bugs in rarely tested code paths at mailbox providers and potentially even open up security problems. I mentioned using a “stunt” DNS server would be one option to do that, and then quite a few people asked me what I meant by that. A stunt DNS server is one that doesn’t
If you’re an ESP with small customers you may have looked at the recent Google / Yahoo requirements around DMARC-style alignment for authentication and panicked a bit. Don’t impersonate Gmail From: headers. Gmail will begin using a DMARC quarantine enforcement policy, and impersonating Gmail From: headers might impact your email delivery.…For direct mail, the domain in the sender’s From: header must be aligned with either the SPF domain or the DKIM domain. This is required to pass DMARC alignment. So everyone who’s using their gmail address to send bulk mail is going to have to stop doing that within the next few months if they still want their mail to be delivered. For any ESP customer that already has, or can be convinced to buy, a domain for their web presence maybe they can be persuaded to switch to using that – though even if they can, onboarding 100,000 technically naive users
If you’re seeing a lot of “451 4.7.500 Server busy. Please try again later” from Office365 this morning you’re not alone. Microsoft are aware of the issue, and incident EX680695 says: Current status: We’ve identified that specific IP addresses are being unexpectedly limited by our anti-spam procedures, causing inbound external email delivery to become throttled and delayed. We’re reviewing if there have been any recent changes to our anti-spam rules to understand why the IP addresses are being limited. In the meantime, we’re manually adding reported affected IP addresses to an allowed list to provide immediate relief.
A lot of beginner questions about email delivery aren’t about broad strategies for success, or technical details about authentication, or concerns about address acquisition. They’re something like: My mail to $ISP is being blocked. How do I contact someone there? Asking a question to your peers about how to deal with a concrete problem you’re having is a great thing to do – you might get immediate help, and hopefully you’ll pick up some technical or industry information and level up some skills along the way. But there are good questions and good ways to ask them, and bad questions and bad ways to ask them. You really want to get the most value out of the answers you get, and you don’t want to waste your peers valuable time. Lets talk about the “My mail is blocked, who do I ask to fix it?” sort of question on an