I’m actually submitting the form to a third party (Campaign Monitor), so I’m not sure how possible it is to pass it through another submit.php type page and add the IP stuff there.

I also understand the downside of using a third party to find the location of the IP, though uploading and sourcing the country code MySQL stuff was a bit beyond me, this time

Thanks again.

say your “action” is “http://site.com/submit.php”, the submission script would be submit.php

In submit.php, you would have all your validation:

check “name” is not empty with:
if(strlen($name) == ‘0′){
//do something on error
}
check “email” is valid with check_email_address() function found here: http://www.linuxjournal.com/article/9585

remember to do something on error again

After validation, you’d then do your IP check before inserting into the database and redirecting to the “Thank you” page.

The only problem would be that $_SERVER['HTTP_REFERRER'] in submit.php would be the page where your form is, so you’d still need that in your hidden fields. Or use cookies, which you’ve already ruled out.

The reason Im saying do the IP stuff in your submit page is:
A) hidden fields can be overwritten by robots
B) you’re depending on a 3rd party script for information, if there’s a hang at the 3rd party site, the form would take ages to load in and you’ll lose your user.

Your theory is sound enough Morris, it’s just the location of certain parts that could be improved to give a better user experience equaling more leads + more money for you.