This WordPress blog has been targeted by Spam bots since it started but recently it has got a lot worse and it is getting tedious to go through all the pending comments and delete the Spam ones.
I’ve seen CAPTCHA used on other sites as a means to distinguish between humans and Spam bots so a quick Google for WordPress CAPTCHA plugins found a few. I wanted one that is updated regularly so it will still work when a new WordPress update is available. The plugin I chose was SI CAPTCHA . This seems to be regularly updated , looks very good, has audio and it works fine – I have had no Spam bot comments since installing. The plugin is free but if you find it useful and want to fund further development then there is a Paypal link – if you think how much time this plugin will save you a donation is highly recommended.
The link on the WordPress plugins site has all the information needed to install. ( Note for Centos check you have php-gd installed – see below ). Basically you unzip it into wp-contents/plugins directory then go to your Admin page , select plugins , then activate the SI Captcha plugin.
There is a nice Captcha support test link to check all is well – my setup failed first time – I got :-
ERROR: GD image support not detected in PHP
ERROR: imagepng function not detected in PHP
This was resolved by installing php-gd RPM. For Centos you would do
yum install php-gd
service httpd restart
Now if anyone wants to add a comment they have to pass the CAPTCHA test which Spam bots are no good at.
Note by default it won’t add the CAPTCHA box to users who are logged in so ensure you have logged out if you want to test it for yourself.
You should see the CAPTCHA at the bottom of this entry.