I have my diary as wordpress blog. Every day I am getting hundreds of comment spam. I had installed comment spam fight plugin and it seems like worked for few days but again I was getting spam messages. I changed the settings of blog so that only logged in user can put a comment. I even disabled comment completely but all efforts were in vein. I tried to find some information on google but couldn’t get the reason. So I thought let me debug the application and check it out why I am getting hunderds of comments everyday. For this, in wp-comments-post.php I wrote a code to write all parameters in a text file so I can check out what’s wrong with application. I can post my comment and see the log file but for spam, there was no log trail. It seemed to me that comments are coming from other? files. so I moved that code into config file and I found that those comments are actually trackbacks. If you want to check if the comment is trackback or not, check the Email value of comment. If you see it empty, it means it is a trackback. I disabled trackback by loggin in site > Options > Discussion and disabling trackback and pingback.
Now I am relieved of comment(actually trackback) spams.