Dear Sebastian

Unfortunately, I got Spammer Registration again with "iWeb - Register" Module also, It's not to much registration, but spammer can OCR Google CAPTCHA also.... and this way also not Safe way....
DNN should be think about that and make Intelligent CAPTCHA Base in Release 7.3.2 like asking 17+9 = ? like this....

I Send this post to tell every one iWeb also could not stop it.... :(

This is Really Bad Restriction for DNN Feature

Hi Robert

Regarding my last post, I noted that it's a few spammer registrations for my first attached website (kindcare.ae) that it was 200 per day no it's less than 10 registration per day and It mean's Ok, but I mean, That Robs can do it... and it's bad news for future....
Right now I install it on 10 other website but they don't attach before but I do it for Defense before attach.

For Me the Very bad News was, after one week from attach to kindcare.ae and yaghoubi.ae both together, My Mail Server also hacked by special Robs or Virus that it can send 1100 Emails per second by None-Registred Email Account. and right now my Dedicated Server IP added to Several Black-List around the world.... last two week was the Baddest Time in my life, maximum pressure and attach to my clients....

Unfortunately, My Experiences is DNN Portals (UI/Content/Administration) and I don't have idea about Technical thing s for Server and mail servers and I help it by my friends or outsource persons... until now, nobody could help me to fix this attach to mail server also, I don't know is it come from that DNN attach or not....

Thank you for your post, and if any on can help me for my mail server (HmailServer) I'll appreciate him/her

I will give this solution a whirl right now.  Like the OP, one of my several DNN sites has been suffering this problem for awhile.

For awhile I thought my site under attack was simply doing better-than-average.  Then I started looking at registration and the bounced emails from the "complete registration" emails going out.  I could tell by looking at the DNN and IIS logs no one was on the site registering.  I confirmed the site was still secure so considered it just a nuisance until the past week the amount of registrations increased 3 fold!

What's odd about the attack is they seem to stop during the evening hours and then pick back up during the waking hours.  I wonder if that's to give the appearance the registrations are legit.

In the end, the people who pull stunts like this has long been a plague to Word Press sites.  I guess DNN has gotten so popular it was just a matter of time before they turned their eyes to DNN sites.