So having thought I had managed to thwart the spammers they are back again. Unfortunately now much more vigorously, so much now that my email provide is threatening to suspend my email account due to the DNN email traffic. I think I have just about tried all the advice I can find on this but none of it has worked.

1) custom registration page 

2) blocking all DNN register URL's

3) updated to latest release of DNN

4) using verified registration

5) changed to use reCAPTCHA

I had high hopes for reCAPTCHA, it has slowed the spam but only slightly. I am frustrated and out of ideas.

I have taken to blocking IP Addresses as this is all I have left. This seems very hard to do and DNN does not seem to log the user registration IP Addresses so I can only block the failed login attempts. Is there an easier way to do this, wish DNN had a block user IP button in account profile!!!

I was never able to eliminate it 100%, I tried everything, upgrading DNN, Re-Captcha, disabling ctrl=register.  What finally seems to have worked for me was to add a new profile property.  It's an Integer property and the label is "What is 2+2?".  I set the validation expression to the number 4.  So basically the user can't register unless they enter 4 in the field.  It's not pretty, but it seems to have worked for me.  You can see it here.

Thanks
Mike