Spam submissions even with captcha in forms

We are having issue of Spam form submission even we have placed captcha in forms, our site configuration is:

joomla: 2.5.3
chronoforms: 4

and another interested part we noticed is, like we have multiple domains pointed to same joomla site, I mean like abc.com is our main site but we have pointed abc.in also to abc.com and our forms are set to send page url with each submission so all spam emails that come to us contains page url other than main domain (abc.com), so need to know does chronoform checks for validated domain while verifying captcha..? because when I manually try to open abc.in and submit with no or wrong captcha it gives message for wrong captcha but we are still getting lot of spam emails everyday.

Hi webnsoft,

If you are getting spam with the fields completed then you probably either have human spammers or bots that are clever enough to beat the Captcha. You may be able to block them using some serverside validation if there is any pattern to the submissions. You could validate the submitting URL if you think that would help.

I don't think that ChronoForms specifically validates the url though there are checks that the form is submitted by the same source that loaded the form.

Bob