How to Stop Forum Spam
Being a webmaster, and having a few websites which have forums on them, it has become apparent to me that spam is a very serious problem, with very few people knowing how to stop forum spam.
You’ve probably noticed a much worse problem if you’re using phpbb, simply because it is commonly referred to as a “walking security vulnerability.” Not only that, but it seems that phpbb is largely targeted by hackers of all types. These hackers have developed numerous bots that run 24/7 with the sole purpose of spamming phpbb forums.
Users of Simple Machines Forum (SMF) and vBulletin are much less at risk, but there can still be spam if certain settings aren’t chosen.
With that being said, here are some general strategies to prevent forum spam:
Human Validation
Default validation forms have been cracked a long time ago, so try to install some mods that use a variety of questions
Email Verification
Don’t let new users post unless they’ve verified their email, including the profile link. Spambots use random email addresses and generally place a link in their profile.
Disallow users from posting links at all
There are mods that can prevent users from posting links until they have passed a certain post or membership time threshold.
Limit time to edit posts
Sometimes people outsource their spamming to humans. These savvy spammers will make regular posts, then go back later and change the posts to contain a load of links. Some even hide the links as their punctuation marks.
Limit signature links
Mods such as vbSEO tack the “nofollow” tag onto all links except those that are explicitly allowed. Also, apply other restrictions to prevent users from having too many signature links. Be careful though, some users get annoyed at not being able to have their link.
Use conditionals
Watch out for memberlist spamming, which is what spammers use to get a link from the members page of forums.
Block common IPs
Get the IP of the spammers that are typically spamming and block them. You can do this from your .htaccess file or even through your forum admin panel.
Censor spam words
Take away the benefit of spammers using anchor text by disallowing or changing certain spam words. Common spam words can be found online and range from drugs to casinos.
Have a team of moderators
Nothing battles spam better than a dedicated team of moderators, especially if you have moderators from around the world. This keeps spam at bay because different moderators are on the board at different times.
Stay vigilant
Spam is changing just as fast as the internet is. It’s like an evolving virus, and the only way to successfully battle it is to keep up to date. Don’t only watch whats going on in your forums, but find out how spam is evolving in other forums. Consider vigilance as your vaccine.
Other resources
You can find just about anything if you have the resources. These websites will help you learn how to stop forum spam.
More details than what I’ve given, and a focus on vBulletin forums.
How to install a spam filter for phpbb, by phpbb
How to Prevent Blog Spam Before it Happens
Focused on preventing spam in blogs, but has great tips about using .htaccess, which is always useful.
Updated with reports of spammers, bots, and scrapers, as well as ranges of IP addresses to block
News, blog, and forum by an anti-spam crusader.
Good luck in your efforts, and I hope you’ve better learned how to stop forum spam!