I’ve been trying to chase down a mysterious problem with emails going missing. The problem with things being missing is that you can’t see them, so it has been difficult to track down exactly what’s going on, but it became clear that we were receiving no email at all from Amazon or Play.com for several months, and that some other mails had disappeared too. I was secretly assuming that I’d screwed something up in the terrifying postfix+dovecot+fetchmail+spamassassin+procmail config on our server, but I couldn’t find any indication of what could be going wrong.
I thought an over-enthusiastic spam filter might be swallowing mails, but it turns out the problem was that I was “forwarding” emails from my domain to my ISP-provided mailbox.
Since the SPF anti-spam system has begun to be implemented, emails from people like Amazon come with SPF policies that make plain message forwarding fail, because forwarding makes it look like emails come from the server forwarding them, when actually they come from the original sender. This makes it impossible to do SPF, so the emails were getting silently deleted.
Now that I know what the problem is, I have even found a sentence describing this on the Wikipedia page on SPF: “SPF breaks plain message forwarding” and this useful article: Why forwarding your email is a BAD idea.
The only solution I can see is to set up a mailbox on my domain host’s site, and stop using the mailbox provided by my ISP. I was only using this mailbox as a holding area before I pulled down the mail via POP3, so it doesn’t actually make much difference to me.
If you’re using GMail you can set it up to pull from a POP3 server, and some other webmail services let you do that too, so using your domain host’s web server doesn’t have to be inconvenient.
Losing email makes me stressed.