spam-prevention

Is there a fast algorithm for finding the Largest Common Substring in two strings or is it an NPComplete problem? In PHP I can find a needle in a haystack: <?php if (strstr("there is a needle in a haystack", "needle")) { echo "found<br>\n"; } ?> I guess I could do this in a loop over one of the strings but that would be very expensive! Especially since my application of this is to search a database of email and look for spam (i.e. similar emails sent by the same person). Does anyone have any PHP code they can throw out there? The similar_text function may be what you want. This calculates the

I have a Wordpress blog and the only user input is the commenting system. I want to totally avoid spam comments. Wordpress comes with Akismet but I can also use Captcha. Which plugin/method should I use? My client doesn't mind users entering verification strings to post comments. If I adopt either Akisment or Captcha will I be able to completely control the spam? Is it possible to use either Akismet or Captcha for a simple 4-digit verification? If not then please also recommend a plugin/method capable of just a 4-digit verification. The captchas seem to be fooled by adept people. The Akismet

I'm getting problems with spam entries in my database through signup form. I have tried many open source Captcha solution, but still facing same problem. I am therefore looking for an alternative solution. What about the solution, where users would have to input the answer to a question? The answer to the question will be a server-side specific word then would this surely defeat a spambot? Would it be better to have a series of simple randomized questions or something like "6 + ? = 9" be better as a question? The only thing that concerns me is that if it's as easy as this to protect a signup

Has anyone been able to successfully prevent spam on their site without placing a burden on your visitor (e.g. CAPTCHA) and without using a centralized spam reporting system (e.g. Akismet) I've found this & it looks promising, but doesn't contain detailed deployment instructions. I want to present my web forms without burdening my users with CAPTCHA like technologies, but also actively automate preventing spam. There doesn't seem to exist a detailed instruction/tutorial on how to implement such a technology. Disclaimer Also, I realize there no silver bullet appropriate to preventing spam. But

Is there any way to consistently detect PhantomJS/CasperJS? I've been dealing with a spat of malicious spambots built with it and have been able to mostly block them based on certain behaviours, but I'm curious if there's a rock-solid way to know if CasperJS is in use, as dealing with constant adaptations gets slightly annoying. I don't believe in using Captchas. They are a negative user experience and ReCaptcha has never worked to block spam on my MediaWiki installations. As our site has no user registrations (anonymous discussion board), we'd need to have a Captcha entry for every post. We

How do we get rid of these spambots on our site? Every site falls victim to spambots at some point. How you handle it can effect your customers, and most solutions can discourage some people from filling out your forms. That's where the honeypot technique comes in. It allows you to ignore spambots without forcing your users to fill out a captcha or jump through other hoops to fill out your form. This post is purely to help others implement a honeypot trap on their website forms. Update: Since implementing the below honeypot on all of my client's websites, we have successfully blocked 99.5%

Some other website use cURL and fake http referer to copy my website content. Do we have any way to detect cURL or not real web browser ? Alain Tiemblo There is no magic solution to avoid automatic crawling. Everyting a human can do, a robot can do it too. There are only solutions to make the job harder, so hard that only strong skilled geeks may try to pass them. I was in trouble too some years ago and my first advice is, if you have time, be a crawler yourself (I assume a "crawler" is the guy who crawls your website), this is the best school for the subject. By crawling several websites, I