You can use captcha security with DJ-Catalog "Ask about this product" form.
This tutorial is about core Joomla ReCaptcha functionality, other plugins may work different and may need different setup
Here's the short tutorial how to do it.
- You need to generate reCaptcha keys at https://www.google.com/recaptcha/admin#list and obtain both SITE and SECRET keys for your domain.
- Go to Extensions -> Plugins and make sure that "Captcha - reCaptcha" plugin is enabled.
- Enter SITE and SECRET keys into plugin configuration and save the settings.
- Navigate to DJ-Catalog2 configuration (Components => DJ-Catalog2 => Options), make sure that "ReCaptcha" plugin has been selected for "Captcha" setting and save the configuration. If your website uses reCaptcha globally then you can select "Use Default" instead.
Now you can use captcha security with "Ask about this product" form.