You’ve probably heard about Apple Mail Privacy Protection. Email marketing chat has been all a-twitter about it since it was announced in June. Skipping over all the “Openpocalypse” panic, what is it and what does it do? Image Loads It’s all about images in email and how they’re loaded (particularly invisible one pixel images that are used solely for tracking). Why...
Cyber Monday
— @TwistedDoodles
The OSI Seven Layer Model
In the 1970s, while the early drafts of the Internet were being developed, a competing model for networking was being put together by the ISO (International Organization for Standardization). The OSI (Open Systems Interconnection) Model broke the work needed to implement a distributed network service into seven separate layers of abstraction, from the physical infrastructure at layer one all the...
Authentication
Some notes on some of the different protocols used for authentication and authentication-adjacent things in email. Some of this is oral history, and some of it may be contradicted by later or more public historical revision. SPF Associates an email with a domain that takes responsibility for it. Originally Sender Permitted From, now Sender Policy Framework. It allows a domain owner to announce...
Alt-text and phishing warnings
For a long time one of the “best practices” for links in html content has been to avoid having anything that looks like a URL or hostname in the visible content of the link, as ISP phishing filters are very, very suspicious of links that seem to mislead recipients about where the link goes to. They’re a very common pattern in phishing emails. /* This is bad: */ <a href="">>...
Link tracking redirectors 2
It’s not too difficult to build your own link redirector, perhaps a few hours work for a basic implementationme, yesterday Yesterday I suggested that link tracking wasn’t too complex, but didn’t really have anything to back the claim up. And nobody trusts developer time estimates. So I cranked DEF CON Radio and wrote a dedicated click-tracking webserver, mostly as a demo of how to use...
Link tracking redirectors
Almost every bulk mail sent includes some sort of instrumentation to track which users click on which links and when. That’s usually done by the ESP rewriting links in the content so they point at the ESP’s tracking server, and include information about the customer, campaign and recipient. The recipient clicks on the link in the email, their web browser fetches the link from the...
New laptop, old reminder
I have a new laptop.
New OS (maybe this year will be the year of Linux on the Desktop?). New hardware problems. New applications. New keyboard layout.
New mail client.
It reminded me of another reason why you want to keep the email address in your From: consistent – it’s something some users will use to automatically load images, which is something you probably want.
CAN-SPAM Again
The US CAN-SPAM act is the primary US legislation covering commercial email. It’s been around since 2003, but I still see a steady stream of questions about it, and the folkloric answers to some of them are all over the place. What does CAN-SPAM require? The important requirements are Don’t use false or misleading header information Don’t use deceptive subject lines Make it...
Gradual DMARC Rollout
Over on twitter Alwin de Bruin corrected me on an aspect of DMARC soft rollout I’d entirely forgotten about. It’s useful, so I thought I’d write a quick post about it. If you have a large mail stream and you want to avoid the Scary Red Flag Day when you turn on DMARC p=reject enforcement and wait for people to complain you can use the DMARC policy “pct=” tag to roll...