I got an email the other day…

…that said bandwidth on this site was about to be exceeded. I have no illusions about this blog — it’s not designed to draw in masses of readers, just those who already know me. I’ll occasionally send out a notice that some new pictures are up, and maybe a few other people will stumble on the site looking for information on diskectomies. But it’s pretty much a project that helps me experiment with web stuff.

So this email was a surprise. A few months ago I’d gotten hit with comment spam, but was able to knock that out with WordPress Hashcash, an elegant script that eliminated comment spam immediately. I’d experimented with authentication images, but the spammers were somehow able to work around it. Hascash, though, took care of it invisibly and effectively, and I’ll get an email every month saying how many spam posts were made. Kind of like the bills a hospital sends, even though insurance already picked them up. Makes me say a big Thank You out loud.

But then the bandwidth messages started coming, and after looking at the logs, I learned a new phrase: “referer spam.” Online poker and prescription meds were hitting me every couple of minutes. Their goal is to get a link embedded in as many databases as they can, increasing their rankings in search engines. Because of Hashcash, they weren’t making it into the database (CJD Spam Nuke keeps track of that), but were still showing up in the logs, meaning they were eating up my bandwidth.

I locked out block.alestra.mx — they’ve done nothing to secure their servers for a very long time, and were far and away the largest single source of referrer spam.

But IP Deny wasn’t quite enough. These guys were sending from IPs all over the world, sometimes only one or two hits before they went to the next one. Working with .htaccess was the next step, but I’m not confident ( or knowledgeable) enough to tinker at that level.

This took care of it. Installation is easy (though I had a little trouble with permissions), and the list of banned referrers easy to edit. Best of all: The messages bounce back to the referring URL. Heh. (I don’t have any way to prove it’s happening, but the images in my head are enough.)

Hashcash. Referer bouncer.

Problem solved.