Hello, Verizon Media Postmaster!

Verizon Media (previously known as OATH, previously known as Yahoo, previously known as AOL) has just launched their new Postmaster Site. Check it out!

As announced on their Postmaster Blog by Lead Postmaster Lili Crowley.

I think it's fair to assume that the legacy AOL Postmaster site is likely to shut down at some point in the near future. It brings a tear to my eye, as that site goes back quite a long time. Here it is in 2003, courtesy of the Internet Archive.

How to Make Sure Important Emails Stay Out of Your Spam Folder

Today, Gizmodo explains how to train Gmail, Outlook/Windows Mail, and Apple Mail on what shouldn't be considered spam.

They left out filter rules in Gmail -- it's pretty easy to create a filter rule in Gmail where the action is "never send to spam" -- this comes in very handy for me, as a lot of the mailing lists I'm on talk about spam and sometimes include samples. Though they might legitimately be spam, if they go to my Gmail spam folder, it makes it hard to see them.

GPT Downtime

Over on the Mailop list (ignore the SSL warning, that is a long-standing issue), people are noting that Google Postmaster Tools has been missing data and/or been glitchy and/or disallowing new domain registrations over the past days. If you had trouble before, you might want to try again now -- a few folks are saying that things seem to be getting better as of today (Wednesday), though it is unclear as to whether or not all missing historical data will be populated.

For more on Google Postmaster Tools, start here.

DMARC Policies Up 250% In 2018


Look at the explosive growth of DMARC implementations! This is great to see.

Read more about it over on dmarc.org.

Gmail SPF Status of Best Guess: What does it mean?

If, like me, you use Gmail to test and check email authentication results, then you're used to seeing SPF results that say pass or fail. But what does it mean when it says "best guess"?

Here's an example of a Gmail SPF results header that mentions "best guess":

Received-SPF: pass (google.com: best guess record for domain of bounce31@b.email.example.com designates 1.2.3.4 as permitted sender)

What this means is that Google's "faking it" -- they are synthesizing a potential SPF record based on what information they can figure out about the domain. The exact rules that go into the synthesized SPF record are unclear. It could be past email history. It could be that reverse DNS between the sending IP address and sending domain match. Or it could be other things. That's not the important bit. The important bit is this: When Gmail tells you "best guess," it means it can't find your SPF record in DNS. That's a problem, and one you should investigate immediately.

In the example above, Gmail is saying that it can't find an SPF record for "b.email.example.com." Google's systems are smart enough to deal with it, so your deliverability to Gmail subscribers is unaffected. But other ISPs do not all have similar "fake an SPF record" functionality. That means that some other ISPs probably will block this same mail due to DNS failures or lack of DNS entries. If you review all your bounces, you'll probably see that this is the case.

And it can be a difficult issue to troubleshoot, if you see those bounces, then test with Gmail, and Gmail says that SPF passes. There's little to indicate that something is wrong, except for that magic phrase "best guess." Keep an eye out for it and know that it's a strong indicator of a potential DNS issue with your sending domain.