I was avoiding commenting on the email open tracking bad take that seems to be going viral round the more gullible corners of LinkedIn. I avoided it for long enough that other folks wrote articles saying pretty much what I’d say. Yay! You should read what Al has to say over at SpamResource ..read more

We use DNS a lot in email, particularly for authentication, so diagnosing why DNS isn’t returning what we expect it to is a pretty common challenge. And DNS responses aren’t exactly the clearest thing to understand. There are two types of DNS server we need to know about. When we publish DNS records for our ..read more

It’s time we talk about cold outreach mail. In the last 2 years the volume and aggressiveness of cold outreach mail seems to have exploded. There are dozens of companies out there who are selling services to companies to facilitate cold outreach. My own sales mailbox is full of requests from companies to help them ..read more

Why is designing spam filters like designing bear-proof trash cans ..read more

Jody asks “Are ‘prefetch opens’ and ‘proxy opens’ the same thing?” Non-human opens An “open” is just someone (or something) fetching a remote image. A non-human-interaction (NHI) open is where some sort of automation fetches the image without human interaction – i.e. it’s fetched when the automation feels like it, not triggered by a user opening a ..read more

If you’re using sendy and you’ve found that RFC 8058 one click unsubscribe fails – or, worse, seems to work but doesn’t actually unsubscribe the user – you should take a look at James’ workaround ..read more

Lots of times I see someone asking a question and they talk about their sending domain. And it’s sometimes not 100% clear which domain they mean by that – and when we’re talking about alignment and reputation if can make a difference. So here’s a list of (some of?) the different places a mailserver uses a domain. Hostnames Machine Hostname: What the operating system running on the mailserver thinks it’s called. If you log in to it and run the hostname command, this is what you get. It might be single word (e.g. pazu) or it might be a fully qualified domain name (FQDN) (e.g. pazu.wordtothewise ..read more

DMARC is the newest of the authentication protocols. It compares the domain in the From: address to the domains authenticated by SPF and DKIM. If either SPF or DKIM pass and they are in the same organizational domain as the domain in the From: address then the email is authenticated with DMARC. I wrote A Brief DMARC primer back in 2014 – when Yahoo deployed p=reject late on a Friday and caused an awful lot of deliverability folks to spend a weekend trying to figure out why so much of their customer mail was being rejected. I still think that post is pretty good and explains things like align ..read more

A common complaint about the advice or answers any deliverability person gives is that the generic answer to questions is: It Depends. This is frustrating for a lot of folks because they think they’re asking a simple question and so, clearly, there should be one, simple, clear answer. The problem is that there is almost never one answer in deliverability and details do matter. Let’s take a common question: How do I authenticate my email so that it meets the new Yahoogle standards? It’s a simple question, and gets the simple answer: you need to sign with your own domain in DKIM and publish a D ..read more

I always want to say “Emails, and Opens, and Clicks… Oh My!” when I’m talking about them. We really want to understand how a mailbox provider perceives the streams of email we send them. Some of the things the provider looks at are technical and objective – is the email coming from who it claims to be coming from? Is there an attachment that contains a virus? We have pretty good insight into those things, as we can look at the mail we’re sending and have much the same information as the receiving mailbox provider has. Did we attach a virus? Is our authentication correct1? But a mailbox provi ..read more