Home >> Why guestbooks, blogs, wiki are spammed and how to prevent spam.

The main task of a spammer is to post links that lead to the spammer's website on websites having high link popularity. In order to improve positions in major search engines such as Google and Yahoo, spammers try to increase the Page Rank of their own sites using huge quantities of incoming links.

Major search engines, in their turn, do their best to stop this evil with the help of advanced filtering algorithms that disclose spammers’ tricks. However, the problem isn't resolved yet and your website can easily become a target for spam attacks.

As a rule, spammers use special programs - bots-that automatically look for vulnerable sites and spam them with hundreds of links. There are several ways to prevent spam attacks of the kind. Here is one of them. First of all, we must protect our site from spam-bots to guarantee that it is real people that leave messages and comments. Second, we use redirect so that search engines don't take spammers’ links into account.

I recommend using Turing test for protection against spam-bots. You need it to install a script that will generate random numbers and show them as images. After this users (site visitors) will enter this number in a special field for comparison. The thing is that bots can not read the text on the images.

Script Auditor v.1.0

<a href="http://php.webmaster-kit.com/">Stop Spam</a>

Working sample

Installation

If your site’s program engine is written in php you can easily integrate this script in the form for comments. If your engine is other than php you can use this script as "stand along".

1. Upload files audit.php and button.php on your server and change chmod to 755.
2. Open file with form (file where visitor leave comments) and put two rows:

   
   This code for image generation:
   
   <img width=120 height=30 src="button.php" border="1">
   
   This field for input:
    
   <input MAXLENGTH=5 SIZE=5 name="userdigit" type="text" value="">
   
   

3. In action script you can use following code:

   
    include "audit.php";
   
    if (audit()) {
         // Visitor entered correct number
    } else {
         // Wrong number
    }
   

The function audit() returns "true" if the number entered by the visitor coincides with the number on the image, and returns “false” in other cases.

Your site can stop any spammer's bots now. The only thing left to do is the redirect. This operation makes spammers’ links useless for search engines, which makes them leave your site at rest. I recommend organizing the function via Google. To carry out this operation you need to change links in comment area like so:

http://www.google.com/url?sa=D&q=URL 

News:

When Google sees the attribute (rel="nofollow") on hyperlinks, those links won't get any credit when we rank websites in our search results.

Visit my <a href="http://www.example.com/">discount pharmaceuticals</a> site.

Visit my <a href="http://www.example.com/" rel="nofollow">discount pharmaceuticals</a> site.

Sample:

Old link:
<a href="http://www.msn.com">MSN</a>

New link:
<a href="http://www.google.com/url?sa=D&q=http://www.msn.com">MSN</a>

Comments:

Name:	juan
Email:	propagation7@yahoo.com.ar
Location:	Salta, Argentina
Date:	Monday 05th of March 2007 04:08:26 AM
Comments:
Thank you very much! It works perfectly. Warm regards from Argentina.

Name:	Dogus
Email:
Location:	Turkey
Date:	Monday 05th of February 2007 05:51:45 AM
Comments:
Thanks for this wonderful script, I was looking for something like this for a couple of days, and your script is just excellent and incredible simple Good Luck !

Name:	Georgia
Email:	geo2@pathfinder.gr
Location:	Athens
Date:	Thursday 11th of January 2007 07:55:08 AM
Comments:

Name:	Loffe
Email:	erik@eloff.se
Location:	Sweden
Date:	Thursday 28th of December 2006 02:01:25 AM
Comments:
This script works brilliant. i could implement it on my website eloff.se in less than 10 min. Amazing Thank you //Loffe

Name:	Johan_et_Pirlouit
Email:	pinlde@hotmail.com
Location:	France
Date:	Wednesday 20th of December 2006 12:51:11 PM
Comments:
One thing is missing in the source files (v1.0) : the name of your web site in the PHP comments ..

Name:	Manuel Avelar
Email:	manuel@pixelcreart.net
Location:	Honduras
Date:	Wednesday 20th of December 2006 08:03:28 AM
Comments:
Hello, Thanks for that great tool, you can see work in www.elaguilanews.com, in the article section, comment form. Thank again Blessing

Name:	fico
Email:	f.f.@f.flolf.pf
Location:	Roma
Date:	Sunday 05th of November 2006 08:56:00 AM
Comments:
Very nice! Where I can download it?

Name:	gizmonet
Email:
Location:	Hungary
Date:	Thursday 02nd of November 2006 01:06:09 AM
Comments:
Thank you very much, this script! This a very very useful thing! Thank You, again! Gizmonet

Name:	Kelsett
Email:	boubaboum@boubi.com
Location:	...
Date:	Tuesday 31st of October 2006 03:07:53 AM
Comments:
Really good

Name:	markus
Email:
Location:	germany
Date:	Tuesday 24th of October 2006 02:22:37 PM
Comments:
great job! thanks a lot!

Name:	buzz
Email:
Location:
Date:	Friday 22nd of September 2006 07:23:55 AM
Comments:

Name:	Roger
Email:	none
Location:	Amstenrade, NL
Date:	Wednesday 20th of September 2006 07:01:33 AM
Comments:
ram cool

Name:	zutas
Email:	none
Location:	kalabybiskes
Date:	Sunday 27th of August 2006 07:56:48 PM
Comments:
sssss

Name:	zzzzzzzzzzzz
Email:	none
Location:	zzzzzzzzzzzz
Date:	Sunday 27th of August 2006 05:43:03 PM
Comments:
zzzzzzzzz

Name:	Steve
Email:
Location:
Date:	Monday 21st of August 2006 05:54:33 PM
Comments:
i use also www.cryptographp.com

Name:	sy
Email:
Location:
Date:	Friday 04th of August 2006 11:11:40 AM
Comments:
t

Name:	Vitaliy
Email:
Location:
Date:	Monday 31st of July 2006 05:51:35 PM
Comments:
IT doesn\'t work in Firefox

Name:	Lucian Tipordei
Email:	lucian.tipordei@gmail.com
Location:	Malaga, Spain
Date:	Monday 17th of July 2006 05:25:58 PM
Comments:
Thanx for sharing your work with us, I don\'t like spammers, they will all end up in jail!

Name:	Lucian Tipordei
Email:	lucian.tipordei@gmail.com
Location:	Malaga
Date:	Monday 17th of July 2006 05:24:09 PM
Comments:
Loved the script! Thanx for sharing your work with us! I don\'t like spammers, they will all end up in jail!

Name:	a
Email:	a@j.com
Location:	a
Date:	Thursday 06th of July 2006 06:59:46 AM
Comments:
just a test

Name:	test
Email:
Location:	test
Date:	Tuesday 04th of July 2006 11:50:52 AM
Comments:

Name:	JF
Email:
Location:
Date:	Tuesday 20th of June 2006 08:32:13 PM
Comments:
This is an example of a working guestbook!

Name:	io
Email:
Location:
Date:	Saturday 03rd of June 2006 10:13:10 AM
Comments:
test

Name:	ivy
Email:
Location:
Date:	Saturday 03rd of June 2006 09:31:22 AM
Comments:
testing

Name:
Email:
Location:	UK
Date:	Thursday 18th of May 2006 01:59:26 AM
Comments:
Ah.. new comments go in at the top of the list As mentioned before, clicking the \"go back\" link after posting gives the \"you entered the wrong number\" message, even if the post was successful.

Name:	ROB
Email:
Location:	ROBOLAND
Date:	Thursday 18th of May 2006 12:49:03 AM
Comments:
HI! i\'M A ROBOT!

Name:	A. Noniempje
Email:	anoniempje@mens-agitat-molem.nu
Location:
Date:	Friday 12th of May 2006 01:15:52 PM
Comments:

Name:	mark
Email:	none
Location:	indiana
Date:	Tuesday 09th of May 2006 12:58:48 PM
Comments:
just a test by a human

Name:	abc
Email:	abc@yahoo.com
Location:	Jaipur
Date:	Wednesday 26th of April 2006 02:40:42 AM
Comments:
Test mail

Name:	peter
Email:	sibas@hotmail.com
Location:	earth
Date:	Monday 24th of April 2006 03:15:52 AM
Comments:
man nice script

Name:	ripodb.tk
Email:	admin@ripodb.tk
Location:
Date:	Monday 03rd of April 2006 07:21:06 PM
Comments:
thanks a lot, our guestbook was getting flooded it was terrible.. now I just have the job of going though 10,000 messagees and removing the spam

Name:	*Comp*
Email:	me@privacy.net
Location:	UK
Date:	Monday 03rd of April 2006 08:27:27 AM
Comments:
Digits not too pretty. Like the ones at junkeater_dot_com, but the script not works so well with php pages...

Name:	nimda
Email:
Location:
Date:	Monday 03rd of April 2006 02:09:05 AM
Comments:
hello

Name:	Ales
Email:
Location:	Czech Republic
Date:	Sunday 02nd of April 2006 04:24:18 AM
Comments:
It doesnt work in Opera Browser!

Name:	Tom Haynes
Email:
Location:
Date:	Thursday 16th of March 2006 08:09:25 PM
Comments:
Sorry, my formatting got clobered. I hope you can figure it out

Name:	Tom Haynes
Email:
Location:
Date:	Thursday 16th of March 2006 08:07:24 PM
Comments:
for godaddy\'s advancedguestbook version 2.3.1 (and maybe others) copy the audit.php and button.php in to the same directory as the existing addentry.php file. Next, you will need to follow the instructions below to add some lines to four files /templates/form.php /lib/add.class.php /addentry.php /templates/preview_entry.php form.php is the html that makes up the \'add entry to guest book\' page the additions in this file add the random image and entrty field for your users. add.class.php contains the function that checks the form entries and other stuff. we are adding the audit validation checks there so the guestbook can gracefully return any errors. addentry.php is the entry point to the entry form functions. We are adding an include statement here so the audit functions work right. templates/preview_entry.php obviously is the entry preview page. We need to make sure that the input from the entry form flows through the preview page so it can be validated when submitted. NOTE: Don\'t add the ### START ADD HERE ### and ### END ADD HERE ### lines at the bottom of the /templates/form.php add... </td> <td bgcolor=\"$VARS[tb_color_1]\" valign=\"top\"><textarea name=\"gb_comment\" cols=\"41\" rows=\"11\" wrap=\"VIRTUAL\"></textarea><br> <input type=\"checkbox\" name=\"gb_private\" value=\"1\"> <font size=\"1\" face=\"$VARS[font_face]\">$LANG[FormPriv]</font> </td> </tr> ###### START ADD HERE ##### <tr bgcolor=\"$VARS[tb_color_1]\"> <td> <img width=120 height=30 src=\"button.php\" border=\"1\"> <font size=\"1\" face=\"$VARS[font_face]\">*</font> </td> <td> <font size=\"1\" face=\"$VARS[font_face]\"> Validation number: <img width=120 height=30 src=\"button.php\" border=\"1\">* </font> </td> </tr> ##### END ADD HERE ##### <tr bgcolor=\"$VARS[tb_color_1]\"> <td width=\"25%\"><div align=\"left\" class=\"font2\">$HTML_CODE<br>$SMILE_CODE<br>$AG_CODE</div></td> <td> <input type=\"submit\" name=\"gb_action\" value=\"$LANG[FormSubmit]\" class=\"input\" onclick=\"if(flag==1) return false;\"> <input type=\"submit\" name=\"gb_action\" value=\"$LANG[FormPreview]\" class=\"input\" onclick=\"if(flag==1) return false;\"> <input type=\"reset\" value=\"$LANG[FormReset]\" class=\"input\"> </td> </tr> </table> </form> ------------------------------------------------------------------------------- in the lib/add.class.php file add... function check_entry($type=\'\') { global $GB_UPLOAD, $GB_TMP, $GB_PG; ### skip to near end of function ### if (!$this->db->CheckWordLength($this->comment)) { return $this->db->gb_error($this->db->LANG[\"ErrorPost10\"]); } ##### START ADD ##### if ($type != \"preview\" { if (!audit()) { return $this->db->gb_error($this->db->LANG[\"ErrorPost4\"]); } } ##### END ADD ##### return 1; } -------------------------------------------------------------------------------- in the top of the /addentry.php file add... include_once $include_path.\"/lib/vars.class.php\"; include_once $include_path.\"/lib/add.class.php\"; ##### START ADD ##### include_once $include_path.\"/audit.php\"; ##### END ADD ##### $gb_post = new addentry($include_path); -------------------------------------------------------------------------------- in the bottom of the templates/preview_entry.php file add... </tr> <tr bgcolor=\"$VARS[tb_color_1]\"> <td width=\"32%\">&nbsp;</td> <td> ##### START ADD ##### <input type=\"hidden\" name=\"userdigit\" value=\"$_POST[userdigit]\"> ##### END ADD ##### <input type=\"button\" name=\"back\" value=\"$LANG[FormBack]\" class=\"input\" onclick=\"javascript:history.back()\"> <input type=\"submit\" name=\"gb_action\" value=\"$LANG[FormSubmit]\" class=\"input\" onclick=\"if(flag==1) return false;\"> $HIDDEN </td> </tr> </table> ------------------------------------------------------------------------------ I know this allows the auditing functions to work but I do not know if it stops bot entries on the godaddy guestbook (it should). However, I offer no support for this modification. Good Luck Tom Haynes

Name:	Cozmo Trouble
Email:
Location:	On the Couch
Date:	Sunday 12th of March 2006 02:24:50 PM
Comments:
Thanx for the code. I finaly got those freakin spammers from flodding our guest book app

Name:	Jesse
Email:	not@available.com
Location:	US
Date:	Saturday 11th of February 2006 06:12:21 PM
Comments:
Thanks!!!

Name:	Richar
Email:	razlpy@gmail.com
Location:	Paraguay
Date:	Thursday 05th of January 2006 06:40:59 AM
Comments: