Can someone give me a regular expression for my blacklist that would disallow any four-consonant (lower case) string? I’ve been getting a lot of spam lately like this one:

Name: Ryan
Email Address: ron@fromru.com

Comments:

Well done!
[url=http://cowbtclt.com/gcqj/uqml.html]My homepage[/url] | [url=http://vprqmclp.com/rsyx/vvwl.html]Cool site[/url]

None of these seem to be real domains, so I don’t know what the point is, but they all seem to have at least four consonants in a row. I figure that there are few real words like this, at least in English, so it would keep out the riff raff without impeding genuine commenters.

[Update on Friday night]

OK, as a commenter has pointed out, this would preclude some actual English word (like “strength”). So let’s go for five consonants. My goal is to err on the side of letting good posts through.

[Update on Saturday night]

It doesn’t catch them all, but I did come up with a good trap for them: q[^ua\ \.\,]

Anything with a “q” in it followed by anything other than a “u” or “a” (or a space, period or comma, so we can write “Iraq”) is blocked. A lot of these things have “q”s inserted in them.

[Another update, a few minutes later, after testing]

I’m getting a lot of false positives.