One more cup of coffee

Debugging email spam blocks

A lot of people in our church use AOL. Because of this, our pastor frequently emails a lot of people with aol.com email addresses.

Or he did, until his email started bouncing as spam. I would argue that sending a copy of the church bulletin to five people is hardly spam, but AOL's servers were insistent.

Al found the phone number for AOL's "postmaster hotline", where he talked to someone that insisted that the problem was that the IP address the church was using had been flagged as a source of spam, and we would need to talk to our ISP.

The problem with this explanation is that it made no sense at all. First of all, the church uses PacBell DSL with a dynamic IP address, so the IP address changes periodically anyway. And, I've never heard of blocking email because of the original source (which can be forged by any idiot anyway) -- you block mail relays instead. You block that because either the mail relay is deliberately sending spam, or because it was configured by an idiot that didn't realize that putting a mail relay on the internet that anyone can send mail through without a password is A Bad Thing.

But you don't block because of the supposed originating IP address. Al even tried, to no avail, to point out the absurdity of this to the AOL rep, asking if it was really their policy to just randomly block email originating from the heart of Silicon Valley because one address might have been used to send spam once.

So I called AOL yesterday. After 35 minutes on hold, I finally get to someone who tells me that no, of course it's not because of the DSL IP address, it must be because of the mail relay. I give him the IP address of the mail relay we use, which is provided by the church's hosting company -- the same one that hosts the web site (except when they do things like forget to start the Apache server, but that's another rant). He looks it up, comes back, and explains that it has no reverse DNS entry. Which I knew. But evidently, once a mail relay gets marked as 'bad' for whatever bizarre reason by AOL, it goes into their blocked list. And, once on that list, the first test that is done of the mail relay is to see if it has a reverse DNS. If not, it doesn't come off the list.

This still doesn't quite make sense to me. There must be some reason for it, I imagine. Perhaps a statistical study of spam has shown that servers without reverse DNS entries are more likely to be used to relay spam?

At any rate, the problem winds up being the one thing that I can't fix on my own. So now we have to wait for Westhost to add a reverse DNS entry. Unfortunately, Westhost is in the middle of screwing up migrating all of their accounts from one server setup to another, and in so doing, has basically managed to screw up every single one of them. When they migrated the church's web site, it took me about three hours to get it running again (starting Apache was the easy part, sadly). In other words, they aren't likely to get to this anytime soon. Meanwhile, my pastor can't reliably send email to a number of church members.

Every so often I read some apocalyptic treatise on how spam is going to result in the death of email. I usually dismiss these out of hands, but more and more, I catch myself wondering. Several months ago, I spent a while trying to convince the University of Michigan that my email relay wasn't sending spam. And, every so often, I notice that some piece of email that meriko sends through my mail relay gets blocked for no good reason. And now I'm fighting AOL over this. And herein lies the biggest problem with spam -- how do you block it, so your email isn't constantly filled with offers of bigger body parts, more money, etc., without causing such terrible headaches for people sending legitimate email?

We have a long way to go on this.

Posted by Mike at September 11, 2003 09:13 AM