A significant commenting problem has surfaced this weekend with Movable Type blogs running version 3.2 or newer. Fortunately this time it has nothing to do with an architecture problem though. Versions of Movable Type from 3.2 up come with a plugin called Spam Lookup preinstalled and activated. One of its defenses is to check a couple of blacklist organisations for known spammers and that check is failing.
Unfortunately, one of the blacklist organisations Spam Lookup uses by default has decided to shut down due to overloading, but instead of just shutting, off, they're blackholing all requests to the address. This means that on any blog using the plugin, Spam Lookup will try to connect for up to 30 seconds before giving up and allowing the comment script to complete its task - the net result being comments that seem to take forever to post.
The address in question is opm.blitzed.org and a note on their wiki states:
Please stop querying the opm.blitzed.org zone. As of May 2007 in order to reduce query load on our servers, opm.blitzed.org is pointing at a blackholed nameserver -- queries will take a long time and result in a SERVFAIL.
If you're running a Moveable Type blog using version 3.2 or higher, you just need to remove this particular address from the list of sources to check within the Spam Lookup plugin's configuration settings. There are step-by-step instruction below for anyone who needs a walk-through.
Folks whose blogs I host, or for which I provide tech support have already had this update applied. No need to do it yourselves, but do mention it to others you know who use Movable Type and may not be aware of the fix. Note this doesn't apply in any way to Typepad.
Click the extended entry for step by step instructions and a screenshot of how to make the change.
Go to your blog's administration section - the area where you normally write your posts. Then click on the Settings link in the left hand navigation panel. On the following page, you'll see a Plugins tab at the top right of the page. Once you click it, you'll see a list of your plugins - look for the section that says SpamLookup - Lookups and click the Show Settings link to the right. Once there, you'll see the text box called IP Blacklist Services. Delete opm.blitzed.org from that list, then click Save at the bottom of the section.
That's it, your commenting should be back to normal.