brokenclay.org/journal

Email Meisterin!

I am feeling like the email Meisterin!

One of my domains has a lot of email aliases. Naturally, they attract a lot of spam.

I was kind of lackadaisical about it because my email provider has such terrific spam filtering that I rarely see spam in my inbox. But some of the addresses that these aliases forward to are AOL (boo! hiss!). And when AOL users report spam, AOL responds by banning the webhost’s entire domain. So the webhost turns around and disables forwards to AOL addresses. Lather, rinse, repeat, about every 2 or 3 months.

Sadly, since I am not the Queen of the World, I cannot just tell these AOL folks to get a real ISP. I need to find some way to make sure they get their mail. DreamHost was no help – their clunky Junk Filter only works for real DreamHost mailboxes, not forwarding addresses. I wasted days (maybe weeks) on trying to get something to work there (including installing and learning procmail, installing and learning SpamAssassin, uninstalling procmail, and uninstalling SpamAssassin). I brainstormed with my RMVR buddy – I wanted to replace all addresses with either real mailing lists or contact forms; he’s enamoured of having all the addresses out there as an open public interface.

So I go on a research rampage. Thanks to Invisible Ink, among others, I have now learned that you can have separate email and webhosting providers for the same domain. This turns out to be an amazingly liberating concept!

Another recommendation I have is to avoid using a web-hosting provider for mail hosting. I read a lot of discussion groups about web-hosting providers and they are pretty much universally clueless about what it takes to be a good mail-hosting provider these days.

I bought another Fastmail account for RMVR, and set up rmvr.com as a virtual domain with them.

Once I was satisfied that emails to anyone@rmvr.com were really going to the new Fastmail account, I started working on the spam filtering. After a couple of days (spam rolled in all by itself; I also forwarded known spam to the account), I felt pretty confident that the false negative and positive rates were pretty low. Then I got going on the forwarding. Fastmail’s Rules screen allows you to forward to one address, but I have a number of addresses that need to go to multiple people. If you need to customize Fastmail’s rules, you can write your own Sieve script. I didn’t find a whole lot of user-friendly documentation out there, but after grepping through some examples, I felt comfortable enough to give it a go.

Here’s what happens to mail now:

First, it’s assigned a SpamAssassin score. If the score is over 10, the email is silently discarded.

If the score is over 4, it’s filed into a junk folder, which I will review for false positives.

Otherwise, it’s checked for one of the forwarding addresses. If there’s a match, it’s forwarded to one or more addresses specified in the script, and copied to a forwarded folder, which I will review for false positives.

If I find there are too many false positives or negatives, I’ll revisit the spam score values.

Sounds simple, doesn’t it?

(I know, because I have bragged, the entire thing will stop working in about 5 seconds. Pride goeth before a fall.)

Katja

3 Comments

  1. Patricia Tryon

    Interesting. I didn’t know that mail hosting could be done separately from Web hosting. That said, I’ve been pretty happy with pair.com’s pretty agressive spam filtering. It isn’t perfect, but it _has_ slowed down the trouble I was having some months back.

    Reply
  2. Katja (Post author)

    DreamHost was managing to identify less than 5% of actual spam.

    So far the new system is about the inverse – one false negative so far, and no false positives.

    Reply
  3. Patricia Tryon

    That’s _good_. From time to time I get a hint of the number of false positives being thrown by the filtering I have in place. I’d worry about it, if I weren’t trying to get OUT of this business :-)

    Reply

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