You are not fooling us with broken bounce addresses
This is a close cousin on my previous blog entry on broken bounce
addresses, but today I'm feeling less
charitable. Right now we have sitting in our mail queues a bounce that's
trying to be delivered to the address
has been for the past ten hours. From past experience I know that this
message will never be delivered; it will sit there until it times out.
Since this is an actual bounce, the original message was not scored as spam (we automatically discard bounces of spam). But this is not fooling anyone about what business 'Your Mailing List Provider' is really in. When you claim to be a legitimate mailing list provider but do not accept bounces back, well, people notice (especially if the envelope sender address looks like something that exists to catch errors and so on). Certainly we do. In fact you are fooling us far less effectively than if you accepted the bounce, complaint, or whatever and silently swallowed it.
(We'd probably never notice that. To do so we'd have to do some sort of analysis of common bounce target addresses or bounce target domains, and that's just not something we'd ordinarily do. The way you catch the eye of most sysadmins is to sit around in something that we pay attention to, such as our mail queues.)
I'd say that I don't know why people do this, but actually I do. It's
pretty easy. If you're setting up a bunch of different sending machines
and giving them all their own domains and hostnames that they'll use
in envelope sender addresses, it's that much more work to have them
listen for incoming SMTP (even if they just discard everything). And you
certainly don't want to
MX all of your sending domains to something
common because that could give people who want to block all of your
activity an automated way of recognizing you.