I'm trying to manage spam entries into my websites' contact forms. Currently using the Drupal Captcha module for Drupal 6. http://drupal.org/project/captcha
Based on this report: http://3dg.me/web/drupal-caching-incompatible-with-captcha - I learned that page caching can interfere with the operation of the module. Is this still relevant? Does this apply to allow image captcha based modules?
Yes, the Captcha module is still incompatible with Drupal's caching. In fact, once it is installed, it gives you a nice warning on Drupal's performance settings page.
The CAPTCHA module will disable the caching of pages that contain a CAPTCHA element.
Most challenge/response modules like this will disable caching. The Honeypot module, which helps in deterring spam bots from completing forms, does that too.
Honeypot uses both the honeypot and timestamp methods of deterring spam bots from completing forms on your Drupal site. These methods are effective against many spam bots, and are not as intrusive as CAPTCHAs or other methods which punish the user.
If you need to avoid spam bots fill forms too quickly, you can use the Honeypot, which disable caching when Honeypot time limit is set. Using only the honeypot field, caching is not disabled.
It depends on the challenge and the module version: If you are using the ReCaptcha module for providing the captcha you may use the current dev version which enables caching, see also issue Add support for cacheable captcha's (recaptcha).
