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CAPTCHA Setup
Discus Professional 4.1 supports a "CAPTCHA" test to attempt to distinguish between humans and "spam bots" when a public post is submitted. This CAPTCHA implementation consists of a six-character alphanumeric code presented on an image, which is displayed to the poster and must be re-typed in order to submit a post.
This feature is experimental which means that its implementation is subject to change or removal at any time. This also means that technical support for this feature is not guaranteed (even to those holding a support contract). In other words, use this feature at your own risk.
For clarity, no CAPTCHA code contains any of the following characters which may be easily mistaken for another: the number 1 and the letter I, or the number 0 and the letter O.
System Requirements for CAPTCHA
Generation of the CAPTCHA image requires the following items to be installed on the server:
Of these requirements, it is unlikely that a customer with a "virtual server" will be able to install the GD module without assistance from the server administrator. The GD::SecurityImage and Bitstream Vera fonts should be installable by the end-user via module loading capabilities included in the Discus software (more on this later).
DiscusWare does not provide support for the installation of perl modules. We do, however, provide links above to the modules and prerequisites, for your convenience.
Configuring the font
For clarity and optimal display, DiscusWare recommends the use of the free Bitstream Vera font. The font can be downloaded from the link above. Any other TrueType font may also be used, at your discretion.
Installing the Bitstream Vera font
Download the Bitstream Vera font from the above link, open the zip file with a program such as WinZip, and extract the "Vera.ttf" file to a location on your computer where you can easily find it.
With your FTP program, access your server and navigate to the Discus administration directory (typically named something like "discus_admin_123456789"). This is the directory that contains the discus.conf file.
Make a directory named "font" (all lower case letters).
Using binary mode, upload the Vera.ttf file from step 1 into the "font" directory created in step 3. Please be sure that the capitalization on the file name is correct (capital "V" and all other letters lower-case). If necessary, rename the file using your FTP client to ensure proper capitalization.
Using another TrueType font
Determine the full path to the font file that you wish to use. (The location of fonts will vary widely by system.)
Edit the discus.conf file, adding the following line and substituting in the full path to the font as indicated:
captcha_font=/full/path/to/font/file.ttf
Installing the GD::SecurityImage module
Before installing the module on your own, check to see if the module is already installed. To do this:
Log in to your administration program as the board administrator (typically "admin").
Go to the Version Manager interface and click the "Version 5" tab.
Check the status for the GD::SecurityImage module.
If you find that the module is not installed, you must install it. If you are the server administrator, use the link above to download the module and follow the instructions therein to install it into the main Perl library. If you are not the server administrator, you can install the components needed for Discus as follows:
Download the GD::SecurityImage module (presently GD-SecurityImage-1.61.tar.gz) from the site linked above, open the archive with a program such as WinZip, and extract the "SecurityImage.pm" and "GD.pm" and "Styles.pm" files. (These are found under the "lib/GD" directory within the archive.) Extract these files to a place on your computer where you can easily find them later.
With your FTP program, access your server and navigate to the Discus administration directory (typically named something like "discus_admin_123456789"). This is the directory that contains the discus.conf file.
Make a directory named "perlpkgs" (all lower case letters).
Navigate into the "perlpkgs" directory you just created and make a new directory named "GD" (all capital letters).
Using ASCII MODE upload the SecurityImage.pm file you extracted in step 1 to the "GD" directory you created in step 4.
Navigate into the "GD" directory you created in step 4 (you should already be there after uploading the SecurityImage.pm file) and make a new directory named "SecurityImage" (mix of capital and lower case letters exactly as written here).
Using ASCII MODE upload the GD.pm and Styles.pm files you extracted in step 1 to the "GD" directory you created in step 6.
Confirm that you did this correctly - the directory and file structure should be:
- discus_admin_xxxxxxxxx
+ - perlpkgs
+ - GD
+ - SecurityImage.pm
+ - SecurityImage
+ - GD.pm
+ - Styles.pm
Verifying that all prerequisites are installed
To verify that all prerequisites are installed, log in to your administration program as the board administrator (typically "admin") and navigate to the Spam Blocker interface. If all prerequisites are available, the "CAPTCHA test for public posts" check box will be enabled (meaning that you can check and uncheck it). If the box is disabled -- grayed out on most browsers -- not all prerequisites are available.
Tweaking CAPTCHA parameters
For future versions of Discus Professional, DiscusWare intends to introduce additional options via discus.conf parameters and Options Manager settings to customize the display of the CAPTCHA image. The front ends to configure these options are not integrated into Discus 4.1. However, they are available by editing the discus.conf and options.txt files. (These tweaks are recommended for only the most advanced users and should not be necessary for most implementations.)
discus.conf parameters
captcha_chars=ABCDEFG... - the list of characters that may be included in the CAPTCHA code. Defaults to 23456789QWERTYUPASDFGHJKLZXCVBNM (all alphanumeric characters except 1, I, 0, and O).
captcha_font=/full/path/to/font.ttf - path to true type font used to generate CAPTCHA code. Explained above.
captcha_length=6 - number of characters in the CAPTCHA code. Defaults to 6.
captcha_pointsize=24 - point size of the font. Defaults to 24. The point size also helps determine the width and height of the CAPTCHA image.
captcha_width=300 - width of the CAPTCHA image. Defaults to twice the point size, times the number of characters in the CAPTCHA code if scrambling is enabled, or the point size times the number of characters in the CAPTCHA code if scrambling is not enabled.
captcha_height=48 - height of the CAPTCHA image. Defaults to twice the point size.
options.txt parameters
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