Designed a guestbook, but it keeps getting spammed! need help?

I designed a guestbook for some one using Php/MySQL and its getting spammed every day, I can't figure out why! Everytime I delete all the entries from the database new spam entries appear seconds or minutes later... How is that possible? What kind of spammer am I dealing with here?

Designed a guestbook, but it keeps getting spammed! need help?
Not a person, but spam bots. They trawl the net looking for unprotected databases into which they can insert their link ridden posts.





As your site becomes more and more well known amongst spammers as an easy target it will just get worse and worse...





Might be worth you building a captcha into the script which should stop most of the problem, if at the cost of accessibility for disabled users. Simply search Google for "php captcha" and you'll find plenty of free scripts.





And if that's an issue then you'll need something even more complex like checking the number of links in a post and screening out based on that.





Edit:





As an alternative to a captcha you could always put a sort of 'secret question' in the form that must be filled in correctly before submission can go ahead. This could be something that only a legitimate visitor to the site would know, so it will likely stump any bot. But it also allows blind people to use it so it gets around the accessibility problems of a captcha.





I've used this method to good effect on a couple of sites. Just make sure you change the question every couple of days or so to keep ahead of them bots :-)
Reply:You can't do anything about it.





Experiment this for me.





Put a blank notebook on light post in Los Angeles. The odds are that even prankster will signed their name and message in the guest book. Leave a phonebook and you get some of them torned. Not everybody is nice when come to greed even when spamming the whole internet. You could ban the spammer's IP address but that the only option you got.





OR...





Maybe do what Yahoo do by creating a random digits for proof that you are not a bot or spammer but still even real life spammer can spend their time doing it. They might give out later but this is your last resort.
Reply:please use some type of verification machanism by using email the guest provides. if the guest fails to verify the mail send by you to the mailbox,the particular record gets automatically deleted within week, also those unverified guest are not displayed.


think it will work
Reply:See if you can incorporate one of those things where you have to add a couple letters and/or numbers in a special form to be able to post it, hope it helps.
Reply:Someone that is smarter than you ;-)





Try looking at the server logs and see if you can track where they care coming from. Block their IP address and then check.





BTW, what is the spam that is being posted?