I’m seeing some questions about TLS and Gmail. Folks are seeing a correlation between sending without TLS and the mail going to bulk.
Has anyone seen this? Are you sending mail with TLS and can’t get to the inbox? Or are you sending mail without TLS and getting to the inbox?
Inquiring minds and all that.
We sent out some W-9s this week. For non-Americans and those lucky enough not to have to deal with IRS paperwork those are tax forms.
They’re simple single page forms with the company name, address and tax ID numbers on them. Because this is the 21st Century we don’t fill them in with typewriters and snail mail them out, we fill in a form online at the IRS website which gives us PDFs to download that we then send out via email.
We started to get replies from people we’d sent them to that we hadn’t included the tax ID number. Which was odd, because it was definitely there in the PDFs we’d sent.
The reports of missing numbers came from Google Apps users, so we sent a copy to one of our Gmail addresses to see. Sure enough, when you click on the attachment it’s mostly there, but some of the digits of the tax ID number are missing.
And all the spaces have been stripped from our address.
The rest of the form looked fine, but the information we’d entered was scrambled. Downloading the PDF from Gmail and displaying it – everything is there, and in the right place.
Weird. After a brief “Are gmail hiding things that look like social security numbers?” detour I realized that the IRS website was probably generating the customized forms using PDF annotations.
PDF is a very powerful, but very complex, file format. It’s not just an image, it’s a combination of different elements – images, lines, vector artwork, text, interactive forms, all sorts of things – bundled together into a single file. And you can add elements to an existing PDF file to, for example, overlay text on to it. These “annotations” are a common way to fill in a PDF form, by adding text in the right place over the top of an existing template PDF.
I cracked the PDF open with some forensics tools and sure enough, the IRS had generated the PDF form using annotations.
All to often we think of filters as a linear scale. There’s blocking on one end, and there’s an inbox on the other. Every email falls somewhere on that line.
Makes sense, right? Bad mail is blocked, good mail goes to the inbox. The bulk folder exists for mail that’s not bad enough to block, but isn’t good enough to go to the inbox.
Once we get to that model, we can think of filters as just different tolerances for what is bad and good. Using the same model, we can see aggressive filters block more mail and send more mail to bulk, while letting less into the inbox. There are also permissive filters that block very little mail and send most mail to the inbox.
That’s a somewhat useful model, but it doesn’t really capture the full complexity of filters. There isn’t just good mail and bad mail. Mail isn’t simply solicited or unsolicited. Filters take into account any number of factors before deciding what to do with mail.
I wear a number of hats and have a lot of different email addresses. I like to keep the different email addresses separate from each other, “don’t cross the streams” as it were.