What is the best way to restrict spammers?

Question

We have some Chinese people spamming forums with their certification links. We are looking for some ideas how we can block these spammers? Block based on IP address is not a best practice.

Any ideas? Please suggest here.

Ibrahim Ersoy · Answer

Retina Scan :) Joke. Lets add some Captcha Control.It wont defeat spammers but effective.

Sam Hobbs · Answer

I am sorry, but perhaps I was not clear. So fist let me explain something that I assume you already know. When we create a link in HTML, that is an anchor ("A") element. The anchor has a href attribute, as in: C-SharpCorner The inner text of the element is the title of the link. For those posts that are spam, the href will be the domain they want people to go to. You can tell the post is spam because of the domain name. Your scripts could enumerate the links in a post (you know, as in my article about web site scraping) and if a link has a domain name that is known to abuse, the post could be rejected or quarantined automatically. It should be quite reliable with few false positives and should catch most posts that are not wanted. They might develop clever ways to get around this but it is easy enough to do that I think it is worth doing.

Mahesh Chand · Answer

Thanks Sam. This is what I was thinking. Implement bad words in the editor and add all spam words to the list. Editor will check if a post has the spam word, just ignore that. Question is, is that enough? Other option seems to be which everybody is doing, have a word verification.

Sam Hobbs · Answer

You seem to have removed most of them and I understand why. That makes it more difficult for people to analyze the problem though. I agree with the descision to remove them. You might however move the posts to someplace that can be referred to by those of us that want to help in the analysis. Based on the two threads I did see, the links are usually for a few specific domains. You should be able to check the links for a specified list of domains, such as domains with ourexam or wiziq. I am not the complete domain names but I hope you know what I mean. There are services such as The Spamhaus Project that provides various lists for filtering email spam. I don't know if their data is useful for forums but it might be.