This mod prevents the posting of topics or personal messages containing black listed urls. It uses the Wikipedia black list and a user created custom black list.
After installing check with your host provider if it uses a HTTP Proxy for external connections and if so enter it in Admin -> Features and Options -> Basic Features.
If the Mod does not catch spam URLs look for the wikipedia_black_list.txt file in /attachments. If it is empty (0 bytes) then you have connection problems. Recheck the HTTP Proxy address and wait for one hour to try again.
CUSTOM BLACK LIST A custom black list can be created. Create a file named custom_black_list.txt in the attachments directory. Each line on that file is a regular expression to be blocked. Do not forget to escape the dots with a backslash.
Sample black list:
intblog\.org # this will block the whole domain subdomain\.domain\.tld # this will block only the subdomain