Comment spam sucks, its as simple as here at Venture Skills blog we get hundreds of spam a day most are caught by Akismet but not all are. If your hosting your own blog or site then no doubt you have tried many combinations. One simple method of reducing spam is a CAPTCHA “Completely Automated Public Turing test to tell Computers and Humans Apart” These provide puzzles which are easy for a human to solve but are much more difficult for a machine.
A client asked me last night if it was possible to block certain countries from accessing his website. He’s concerned about the “axis of evil” and their comrades downloading his software. The task is easily accomplished, although it’s like using a sledge hammer to tap in a finishing nail. He didn’t seem too concerned that we could accidently block Uzbekistan in the process. Unfortunately his entire site uses plain .html files, no dynamic scripting. This led me to using a slightly creative solution with .htaccess
This short article will show you how to make email addresses clickable and working in your pages but still keep them obfuscated for spam bots
“ModernCaptcha” is a simple script in order to prevent spam in a very user friendly way. In a few words, your visitors don’t have to type some characters as you see on the most websites, the verification is made by choosing the company name belonging to the logo that is show.
This example shows a simple method of decoding "CAPTCHA" (Completely Automated Public Turing test to tell Computers and Humans Apart) correctly into usable variables for processing. There is no 100% guarantee that it would successfully decode the CAPTCHA (Maybe about 90% or more) but it is a start. The sample CAPTCHA we are going to decode comes from a very popular file hosting service called "Rapidshare". Why are we using it is because the the CAPTCHA have a fixed offset, simple character font and a clear background.
You may be thinking just exactly what is a captcha? Well you are likely to have already seen them across the web. They are those little images with a code on the front that you type into a box in order to submit something. This kind of system helps to prevent automatic submitting of an operation by some kind of program or robot. In this tutorial I will show you how to make a CAPTCHA just like the one below. Its not the most advanced captcha available because it uses a simple system font and nothing more.
Captcha is the name for the images with random letters and some distortion that appears on each and every forum these days and even here on dublish. The purpose is to prevent the sites from spam.
phpBB is "an open source, flat style, message board written in PHP." Because thousands of people use it with little or no modifications, it is a very popular target for spammers. They can use bots to automatically fill out the registration forms, including "clicking" on the activation link inside e-mails. A CAPTCHA is some sort of challenge that will (in theory) be easy for a human to solve, but hard for a computer to. Typically, they are implemented as a distorted word that the user must enter to complete the form.
Anyone who has an email address can tell you that spam is one of the great banes of the online world. But it's not only distant servers owned by the spammers that are to blame. It may even be your very own server. Insecure PHP scripts have provided great opportunities for spammers to abuse other's resources to send out their spam. In particular, it's the mail() function that can be abused. I myself was the target a few months ago when I noticed spam being sent from an old form on my server that I'd forgotten about. This month's article looks at techniques that can be used to harden your mail form, and reduce the chances of it being misused.
This is a tutorial on how to make your own (very simple) CAPTCHA protection using PHP to create a dynamically generated jpeg image. This is useful for preventing comment spam. I have a working demo available, and I also use this technique to protect my scratchpad and weblog comments. You can download a zip file with all the files used in this tutorial.