Apache, the server and not the Indian tribe, is a fickle mistress. She is more than a little unpredictable, or at least it feels this way on Site5. While I realize that Apache is a web server, a computer who should be very logical, often times I notice very odd behaviour. Maybe it is the server setup, caching, or even traffic volume, I do not know. I do know that if you have some error in your htaccess file, the Apache server will then display a combination of ip addresses and host names. Once you fix the error, which no one can point out and there is no error message to go by, you will be back to only ip addresses.
Does your raw access log display a host name of “0”, or zero? Very odd, is it not? I have been struggling with this for a couple of months, and my ISP Site5 had no answers. It turns out that one of my spammers, NFORCE_ENTERTAINMENT, puts an unprintable character into their host table, so that when my ISP looks them up, they display the unprintable character in my log as “0”.
Trying to control your site’s spam can be challenging. If you try to ban an IP that is simply 0, or a host name of “0” you will fail, because there is no zero in their host name, but an unprintable character. Ban these guys instead.
