Simple Machines Community Forum

1) What is "spam"?

Spam is the abuse of electronic messaging systems (including most broadcast media, digital delivery systems) to send unsolicited bulk messages indiscriminately. While the most widely recognized form of spam is e-mail spam, the term is applied to similar abuses in other media: instant messaging spam, Usenet newsgroup spam, Web search engine spam, spam in blogs, wiki spam, online classified ads spam, mobile phone messaging spam, Internet forum spam, junk fax transmissions, social networking spam, television advertising and file sharing network spam.

Spamming remains economically viable because advertisers have no operating costs beyond the management of their mailing lists, and it is difficult to hold senders accountable for their mass mailings. Because the barrier to entry is so low, spammers are numerous, and the volume of unsolicited mail has become very high. The costs, such as lost productivity and fraud, are borne by the public and by Internet service providers, which have been forced to add extra capacity to cope with the deluge. Spamming is universally reviled, and has been the subject of legislation in many jurisdictions.

People who create electronic spam are called spammers.


2) Forum spam

Forum spam is the creating of messages that are advertisements, abusive, or otherwise unwanted on Internet forums. It is generally done by automated spambots. Recent trends shows increasing number of human spammers.

Most forum spam consists of links to external sites, with the dual goals of increasing search engine visibility in highly competitive areas such as weight loss, pharmaceuticals, gambling, pornography, real estate or loans, and generating more traffic for these commercial websites. Some of these links contain code to track the spambot's identity if a sale goes through, when the spammer behind the spambot works on commission.

Spam posts may contain anything from a single link, to dozens of links. Text content is minimal, usually innocuous and unrelated to the forum's topic, or in a very old thread that is revived by the spammer solely for the purpose of spamming links. Some text is included to prevent the post being caught by automated spam filters that prevent posts which consist solely of external links from being submitted. Full banner advertisements have also been reported.

Alternately, the spam links are posted in the user's signature, in which case the spambot will never post. The link sits quietly in the signature field, where it is more likely to be harvested by search engine spiders than discovered by forum administrators and moderators. Some forum engines, including SMF, offers their users possibility to add a link under their avatar. This may also be used, and usually information hidden in this field is very unlikely to be spotted by administration.

Trends are changing very fast. Recently, one of SMF users reported a new way to hide the website in by spammers in user's profile, as in example [1]:

Quote<td><b>Website: </b></td>
   <td><a href="http://www.ro-bot.de" target="_blank"></a></td>

3) Spam prevention
   
Spam prevention and deletions measurably increase the workload of forum administrators and moderators. The amount of time and resources spent keeping a forum spam free contributes significantly to labor cost, and the skill required in the running of a public forum. Marginally profitable or smaller forums may be permanently closed by administrators.   

Most forum software, including SMF, have ability for creating different member groups [2]. Different membergroups may use different sets of permissions, such as ability to post links, include links in their signatures, access to certain parts of the forum, etc. Assigning new members to a membergroup with limited features might have a positive effect of not giving spam users a chance to advertise their services.

Best idea to eliminate spam, is to cut out spam registrations. There is a number of ways to achieve this.
- employ CAPTCHA [3] (visual confirmation) routines on the registration pages to prevent spambots carrying out automated registrations. Simple CAPTCHA systems which display alphanumeric characters have proven vulnerable to optical character recognition software but those that scramble the characters appear to be far more effective.
- request email confirmation for newly created accounts. this way spammer needs to confirm his email address by clicking the confirmation being sent by the forum engine in order to fully activate their account.
- some forums employ manual activation by administration. this wat, forum administrator may check the legitimacy of a new user before accepting or refusing registration.

All SMF approved mods for Spam Prevention may be found here: http://custom.simplemachines.org/mods/index.php?action=search;type=19
Later in this article we will demonstrate which ones may be helpful against different kind of spammers.


3.1) Registration control

Apart from default prevention methods built in SMF, additional measures may be used. Usually they are being provided by 3rd party modifications (mods).
Here is a list of mods that will help you to target spammers during the registration process:
- Anti-Spam Verification Questions for SMF 1.1.7 - http://custom.simplemachines.org/mods/index.php?mod=1516
- Avatar Verification (1.1.10, 2.0 RC1.2, 2.0 RC2, 1.1.11) - http://custom.simplemachines.org/mods/index.php?mod=2182
- reCAPTCHA for SMF  (all versions) - http://custom.simplemachines.org/mods/index.php?mod=1044

Note: this list doesn't include mods that are targetting spammers by an "authoritative voice" method. This method uses 3rd party resources, such as list of known spammer's IP addresses, their email details, and other, which may help to detect the spammer. Those method, and mods that employs it, will be explained in the last chapter of this manual.


3.2) Posting limits

In order to limit the amount of spam, administrator may force users to wait for a short interval between making posts to the forum, thus preventing spambots from flooding the forum with repeated spam messages. In SMF, this may be tackled by setting a time interval between sending two messages from the same IP address [4]. For both 1.x and 2.x this may be found here:
* Administration Center » Posts and Topics » Post Settings » Time required between posts from the same IP
By changing the number here, we change the amount of seconds between accepting by SMF two posts from the same IP address (which usually means the same computer).

Some spammers try to send Personal Messages (PMs) instead of posting rogue links. SMF allows to limit a number of PM sent hourly, you will find appriopriate setting in membergroups settings.

There is no built in method to limit the amount of posts an user may send hourly in SMF. Additionaly, there is no mod for such available at the mods page at this moment. So apart from setting a time interval between sending two posts, there is no other way of limiting an user to flood the forum with their posts.

3.2.1) Limiting posting links

As most of spammer's post are just links to other websites, another approach is not to allow spammers post links. This may be achieved different ways, such as disabling BBC for certain groups, or using mods to limit spammer's capability.
- Anti Spam: prevents posting links by group (1.1.4) - http://custom.simplemachines.org/mods/index.php?action=search;type=19;bool=and;asc;start=0
- Anti-Spam Links (2.0 RC2, 2.0 RC3) - http://custom.simplemachines.org/mods/index.php?mod=2404
- Spam Black List (1.1.4) - http://custom.simplemachines.org/mods/index.php?mod=467
- Stop Spam Links (1.1.9) - http://custom.simplemachines.org/mods/index.php?mod=1855

and another one which target only guests (when you enable guest posting on your forum):
- No Spam by Guests! (1.0.5, 1.0.6, 1.0.7, 1.1 RC1, 1.1 RC2, 1.1 RC3, 1.1.1, 1.1.2, 1.1.3, 1.1.4) - http://custom.simplemachines.org/mods/index.php?mod=369


4) "Authoritative voice" method

Using an external filtering service, to get a verdict if the data is spam or not. There is many 3rd party sites which would allow to check user's data against various databases.

- Akismet Spam Protection (1.1, 1.1.1, 1.1.2, 1.1.3, 1.1.11, 2.0 RC2) - http://custom.simplemachines.org/mods/index.php?mod=544
- httpBL (1.1.10, 1.1.11, 2.0 RC2) - http://custom.simplemachines.org/mods/index.php?mod=2155
- Project Honey Pot MOD (1.1.9, 1.1.10, 2.0 RC1-1, 2.0 RC2, 1.1.11) - http://custom.simplemachines.org/mods/index.php?mod=1849
- Stop Forum Spam (1.1.7, 1.1.8, 1.1.9, 1.1.10, 1.1.11) - http://custom.simplemachines.org/mods/index.php?mod=1519
- Stop Spammer (1.1.11, 2.0 RC2) - http://custom.simplemachines.org/mods/index.php?mod=1547

5) Other solutions

- Bad Behavior mod (2.0 RC3) - http://custom.simplemachines.org/mods/index.php?mod=2502

Bad Behavior complements other link spam solutions by acting as a gatekeeper, preventing spammers from ever delivering their content, and in many cases, from ever reading your site in the first place.  Bad Behavior analyzes the delivery method as well as the software the spammer is using.  In this way, Bad Behavior can stop spam attacks even when nobody has ever seen the particular spam before.
Bad Behavior is designed to work alongside existing spam prevention services to increase their effectiveness and efficiency. Whenever possible, you should run it in combination with a more traditional spam prevention service.

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Resources:
Wikipedia.org
SimpleMachines.org

[1] http://www.simplemachines.org/community/index.php?topic=375738.0
[2] http://docs.simplemachines.org/index.php?topic=167
[3] http://en.wikipedia.org/wiki/CAPTCHA
[4] http://en.wikipedia.org/wiki/Ip_address


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Note: keep in mind this is a Work In Progress. If you found any information that should be included in this manual, please give feedback and I will include it. There is more content to come, so be patient!

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- updated on 01.07.2010

Very nice post.

If there was a 'Like' button, I would have been hitting it continuously. ;)

flapjack, would you like this moved the the Tips/Tricks area?

why not, as long as people will be still able to post in it, I may not cover all aspects of spamming myself :)

Moved.

Nice article but please note that Bad Behavior mod (2.0 RC2 & RC3) (http://custom.simplemachines.org/mods/index.php?mod=2502) does not use a third party site.  It uses php code developed by the Bad Behavior core (http://www.bad-behavior.ioerror.us/) author after many years of research to inspect the visitors internet information and rejects them before they can get a chance to post on your forum.  The package has no external links, has had extensive testing and is extremely fast.
8)

I guess if you had to call it something "gatekeeper" will fit it best.
:)

you are correct. care to write (snatch from author's page) couple lines of how it actually works, and why it's one of the best solutions available? ;)

If I had to pick a couple of lines:
Bad Behavior complements other link spam solutions by acting as a gatekeeper, preventing spammers from ever delivering their content, and in many cases, from ever reading your site in the first place.  Bad Behavior analyzes the delivery method as well as the software the spammer is using.  In this way, Bad Behavior can stop spam attacks even when nobody has ever seen the particular spam before.

Bad Behavior is designed to work alongside existing spam prevention services to increase their effectiveness and efficiency. Whenever possible, you should run it in combination with a more traditional spam prevention service.

I am too tired to write my own stuff this morning.   O:)

Hi, I was 'one of SMF users reported a new way to hide the website in by spammers in user's profile'.

I have reCAPTCHA, Anti-Bot Registration Puzzles, and Stop Spammer all installed, yet I still get from 5 to 10 spam registrations per day. Probably humans hired in 3rd world countries doing it. 50 cents/hour is good pay in many of these countries.

Post Spam:
These days, most spammers don't post in my forum. If they do, posts get flagged pretty quick by users. That said, some spammers copy/paste text from other parts of the forum to give the impression its a legit post. Often times its out of context or seems too much out of place, but most users never notice and therefore don't flag. It doesn't appear to be automated, but whenever it is automated, we are in deep s&$t.

Profile Website Spam:
For the last year there was a lot of spam website links posted in the website line of spam bot user profiles. This is fairly easy to delete.
Search your member database for users with zero posts and a website of *.*
99% of those are spam bot accounts, and will take seconds to delete.

Signature Spam:
But most recently, spammers have found a way around my above solution. They instead post spam links into the signature section. SMF has no search option for signatures, forcing you to open up profiles manually. I get ~30 registrations per day (I have a large forum), so its a pain in the arse to do this. I could of course install a 'must post X times before signature allowed' mod, but that'll either encourage spammers to post X times, or make it impossible to identify it as a spam account (no spam links). If only SMF had a 'search signature' mod . . .


That said, for all my spam defenses touted as perfect a year or two ago, spammers have found a way around them. reCAPTCHA no longer stops them, for example. I can even see a spammer filling the Stop Spammer database with so much false information it becomes useless. Point being, we have to continually change and diversify our defenses every year, so I doubt there will ever be a forgive and forget solution for a webmaster.

ps - I'm thinking of installing the MOD Honeypot, but their site is down for heavy maintenance right now . . . but I doubt it'll help against 3rd world human spam registrations.

as for signatures, there's already a mod for 2.0. you can also disable signatures for a given group using a simple hack injected in template files, and setting profile as off-limits for people that are not logged in and robots

You can disable signatures for any group with permissions. The only template hack you need is if you're planning on hiding them from guests.

I don't want to disable signatures. What will happen is the spam accounts will still be created, but since they won't do anything spam like, I wouldn't be able to identify and thereby delete them. 30 spam accounts a day, for 1 year, is almost 11k fake members.

I'd rather a search signatures option.

I was getting several a day.  Plus a bunch of bandwidth wasting hits on my site.

I have not seen a fake spam account for several moths and now my bandwidth is under control.

Besides blocking all Countries that are not in my target area I have the following spam prevention installed:

• old version of crawlprotect --  custom edit by me
• Bad Behavior  -- strict mode
• httpBL "Honey pot" --  45/10/30
• Stop Spammer
• Avatar Verification --  over 100 images

Nothing, nadda, zip!
;D

How many regular members do you get signing up though, out of interest?

/me is curious to know the site to see if it considers me a spammer...

My site is not a heavy traffic site with 75-180 guests/ day.  I see 2-3 new members a month.   Yes, people have logged in since my anti-spam measures.
:P

I do not block the UK.  Go ahead and see if you are a spammer:  [edit:  test was completed the link was removed]

Well, it let me onto the registration page, 3 of the avatar based images were broken on first load.

And it let me on. (test_signup, if you want to delete the account)

I have to admit I was a little surprised at the captcha not having any noise in the image.

All in all, didn't feel much more cumbersome than normal sign up and if it keeps the spammers out, go for it.

Ok I will delete "test_signup".

The broken image issue is from the "avatar_verification" mod.  In the past I would fix the mod but in all honesty whenever I do that a revision comes out right after I do it.  Besides I do not know much about images in SMF and would have to spend a bunch of time doing it.  So I set it to unlimited login attempts just in case the image to pick was messed up.  I guess one of these days the mod author will find the problem.
8)

The spammers were reduced with each change/ mod but it was not until I finished Bad Behavior that my spammer count dropped to zero.  The spammer attack was why I made the mod in the first place.  They made me mad!  O:)

Anyone know when the httpBL "Honey pot" will be out of maintenance? Its been like this for at least a week:
http://www.projecthoneypot.org/

I also just added image verification.

But I'm very convinced its humans doing the registration and not bots . . . so not sure how much either will help . . . probably just slow them down a few seconds.

add 2-3 niche specific questions during the registration process

The Avatar Verification mod is useless, lol. Its as if it didn't even phase the spammers for a second . . . and its not just one spammer that got in within the last day, either.

Well, it probably slows them down about 5 seconds per registration, so I guess its better than nothing . . . This just shows that its probably paid humans and not a bot thats doing the registrations.

Adding niche questions won't help, it'll only take a day or so for the spammer to work around it. I'd have to make up new questions every day.

Project Honeypot will be back May 5, 2010.   :-X

Humm, you have 1.1.x bummer, looks like you are a victim of the Forum Poster (http://fp.icontool.com/) program.  Most of the time they hide behind a proxy.  Then they first try automatic posting.  Then manually sign in.  Then they switch into automatic posting.  There used to be 180 of them hitting my site every day.  A few times they assaulted me with many hits to see if they can find a hole in my protection but the BB (http://custom.simplemachines.org/mods/index.php?mod=2502) cache feature tossed them with ease.  Now I reject one to two of them per day.
:o

Though BB can take care of them by blocking just the evil proxies, I do not have the energy to re-write it for 1.1.x so, you can see if Proxy Blocker will slow them down.  Or upgrade to 2.x?  Chances are they will eventually turn off the proxy and try it in the buff.  Then BB and/ or honeypot can catch them.  :P

Hmmmm thanks butchs!

Its been 30 hours, and no new spam accounts (that can be identified as a spam account).

Proxy Blocker appears to have stopped the majority of them, while Stop Spammer blocked the rest.

I give them a max of 6 months before they figure out a way around this and I get spammed again.


I have the below also installed, but they are all useless beyond slowing them down a few seconds:
reCAPTCHA
Anti-Bot Registration Puzzles
Avatar Verification

reCAPTCHA and Anti-spam link I might use.

Quote from: societyofrobots on May 03, 2010, 01:56:17 AM
Hmmmm thanks butchs!

Its been 30 hours, and no new spam accounts (that can be identified as a spam account).

Proxy Blocker appears to have stopped the majority of them, while Stop Spammer blocked the rest.

I give them a max of 6 months before they figure out a way around this and I get spammed again.


I have the below also installed, but they are all useless beyond slowing them down a few seconds:
reCAPTCHA
Anti-Bot Registration Puzzles
Avatar Verification

Maybe a week or two.  By then you should have the honey pot going.  :)

Nice post, I will continue reading it tomorrow.

Excellent tip, i'm sure i will use it :P

Quote from: Arantor on April 29, 2010, 01:57:50 PM/me is curious to know the site to see if it considers me a spammer...

Someone should code the "Arantor Prevention Mod" :P

Arantor Prevention Mod? Really, it's quite simple.

All you have to do is insult me, my work and so on until I get so annoyed I leave. Almost happened here a few times.

Quote from: Arantor on May 09, 2010, 11:48:04 AM
Arantor Prevention Mod? Really, it's quite simple.

All you have to do is insult me, my work and so on until I get so annoyed I leave. Almost happened here a few times.

Yep, but, someone could create a mod that automatically do that every time you post, as simple as that :P

There's always the Annoy User mod :P

I was wrong, it wouldn't take them 6 months to get around it. It took them 8 days.

The same spammer is hitting me on a daily basis now, every day he has a new email and IP so he bypasses the Stop Spammer database.

My theory is that he is using a bot network and not a proxy. Or the proxy just isn't being properly blocked. Or maybe the Tor network?

On the bright side, it appears only one of the spammers have so far beaten the system.

Project Honey Pot is also still down. Even so, my money is on the spammers ability to get around it, to be honest.

sigh . . .

I would like a way to trigger a ban when a user adds a link to their signature.

thank you  ;D

hi all, this post is greeeeeat!!!  i been looking all over for this kinda post.

i have a forum at allnigeria.info, and i noticed that some users keep posting the same stuff, esp adverts, attimes 4 or more times at the same period or over some days in different boards of my forum. this can be irritating. and i am tired of constantly deleting these annoying posts.

my question is: are there mods that can help prevent posting the same stuff over and over on the same forum?

thanks, as i wait in earnest anticipation

I don't think so, but there are mods to help prevent those users from registering. Take a look here:
http://custom.simplemachines.org/mods/index.php?action=search;type=19

Quote from: butchs on April 29, 2010, 01:57:15 PMBesides blocking all Countries that are not in my target area I have the following spam prevention installed:

How do you block countries? This is my biggest problem at the moment, as I'm getting loads of spam registrations from overseas, but it's a pretty UK specific site.

Thanks for any help :)

If your host uses GeoIP you can set up your htaccess file to block many countries.  So ask your host if they offer GeoIP?

http://www.blockacountry.com/

http://www.countryipblocks.net/

I'm not sure about GeoIP, but they seem to have something similar that they call IP Deny Manager:

(https://www.simplemachines.org/community/proxy.php?request=http%3A%2F%2Fi255.photobucket.com%2Falbums%2Fhh133%2FTippon%2FStuff%2Fth_IPDeny.jpg&hash=948fd2843fd97ea7cadc53489df3ff3438496402) (http://s255.photobucket.com/albums/hh133/Tippon/Stuff/?action=view&current=IPDeny.jpg)

So I'll so some reading up and see if that'll do it. Thanks for the advice :)

Flapjack: I've just seen your links while posting this reply, so thank you :) I'm gonna have some food and then get my reading head on :)


EDIT: Added a .htaccess file to deny what appears to be the most common I.P. address ranges that I'm having problems with, so we'll see how that goes.

Thanks again guys :)

QuoteThanks for sharing this tips! I got an idea about this spam! Hope more tricks to come from you!

sure wish SMF would improve spam solutions built in the program, for those of us not comfortable editing the files. :)

seems the options for blocking bots from joining are limited... I tried 2 mods and neither one worked. :(

seems that the captcha built into smf no longer works... a shame.

sorry but you need to give some more details, not "I tried 2 mods and neither one worked."

How do you stop a banned user from posting to your forum?

I have installed a httpBL and Stop Spammer bots and although they did stop some registrations I now get a banned user posting messages to the forum.

Help?

Quote from: Utech22 on May 03, 2010, 11:42:03 PM
Nice post, I will continue reading it tomorrow.

Love it! A content-free post, and obvious spam in the avatar and signature.

One thing everyone is missing here is that it does no good to have only a "hard shell" or "hard crust" defense to try to keep spammers from signing up in the first place. You can reject all the signups you want based on the inability of a bot to solve a visual puzzle or answer questions, and many will still get through (by using humans to do the signup). You can reject signups by email address or use of proxies or by IP address range, and you risk turning away valuable members (especially if you desire worldwide membership).

Any forum needs, in addition, "defense in depth" measures to detect spammers by their content or behavior. For content, you can look for keywords and phrases (after turning v1@gra into you-know-what). You can look for blocks of text copied from earlier posts. You can be suspicious of new members trying to spew out dozens of posts on their first day. You can demand that new members solve a visual puzzle and/or answer questions for their first N posts. You can ban post and signature links for new members. You can follow links and see if they go to commercial-looking sites, and selectively disable those links. There are lots of things a forum could do to flag possible or probable spammers. It would be good to automatically disable member accounts that trip the detectors, or are flagged by other members, or at least hide posts until they can be reviewed.

As spammers get more sophisticated, we have to fight back with more elaborate defenses. Simply making the crust harder, but leaving the interior soft and gooey and delicious, won't slow spammers for long. I have some more thoughts on this in my sig > Projects that you might like to browse.

interesting well written article thank you

I'd be happy enough ( I think), if I could just block all other country ip's except for the US.

Anyone know how this is done or have a link to same?

Quote from: etbrown4 on May 21, 2011, 01:05:10 AM
I'd be happy enough ( I think), if I could just block all other country ip's except for the US.

Anyone know how this is done or have a link to same?

I want the same thing - well, almost.

I want to be able to block all account registrations except for those coming from the USA or Canada.

My forum is focused exclusively on a region of the US and Canada.  I do not want any users registering from Ukraine (about 30 of those today so far, and I expect another 10 before I go to sleep), Russia (a dozen of them), China (half dozen) or elsewhere.  None of these overseas users are "valuable" to me - they are not welcome, even if 1 out of 10,000 is not a spammer.

There's really no way to do this?

If a spammer wants to get into any site , even though all ip's are blocked out of the US/Canada IP range .... All a spammer with have to do it to use a proxy with a IP from US or Canada. Just when you think that you have all IP's that are Blocked, Well ... Here comes IP V6 knocking at our own site. Our next block of IP's from Arin, will be in the IP v6 range ( From the ISP that I work for ).

We can't win for loosing, for spammers will always be a pain in our @**es. All we can do it just make it harder and to make spammers inpatient for answering more questions b4 they post, and maybe that person/bot will just move on to another site. :)

There are some spam mods that claim to work decent, but nothing so far is 100% spam proof without denying innocent new members.

Ive had alot of issues with spam in the past pretty much any time I use any CAPTCHA Now I just use SA Facebook and make it Registration Method Facebook only.  Still get spammers but they don't register.

If ya want to check how it looks
spicelitelust.com

There is a trick to using the two registration questions verifying that the person is a human.

You can fill out the anti spam section and provide the required questions and the mandatory answers.

We thought we had accomplished this months ago - only to find that we had not succeeded. :(

The quirk, and almost bug, is that after you do all that input the is a tiny checkbox at the bottom of the page and if you don't check it, you don;t have antispam really working.

We only found this by accident when we tried a sample signup and the questions were not asked.

This lillte checkbox would be best highlighted or moved to a more prominent place. :)

Good news though. With those anti=bot questions really working - our spammer signups have dropped to ZERO.  That's progress!

The forum will be clean and spam free if all the members are willing to help the moderators by clicking "Report to moderator". Some site are using the filter like a certain post should be approved by a moderator before it become visible. It that sense we can avoid spam posts, however, it's a tedious and time consuming work for our moderators.

I have to admit I was a little surprised at the captcha not having any noise in the image.

All in all, didn't feel much more cumbersome than normal sign up and if it keeps the spammers out, go for it.

Very nice post!!!!!!!

I managed to completely tackle all spam on my forum by doing a few simple things myself- although I still get a few profile link spammers still- but their links are no-follow.

Thank you for this tutorial.

Thanks for sharing this with us..And i would like to say that it is a wonderful site..I liked it very much..I am sure of visiting this site very often..

Is it possible to limit those that can register to a certain domain?  For instance, if every member of my forum was to be a part of a certain organization that gave out email addresses to those who were members, could I filter out any registrations that did not end in: @myorganization.org? 

If so, can someone detail how to do this?

j razz

This has been discussed before. Basically, you could modify the code to "invert" the ban-by-email-domain test. If a registrant's email matches any domain in the list, instead of failing it (banned) it would pass, and vice-versa if it's not found in the list. I'd be surprised if there wasn't a mod already to do this -- have you searched?

I did run a search and that is what brought me to this thread.  Apparently I don't know the terms to search for, but your post is helpful as it gives me some terms to look for in search (Ban-by-email-domain test). 

Thanks MrPhil.

j razz

I have managed to eliminate automated spammers registering on my forum by simply adding two questions to the registration procedure. The questions are not difficult to answer for a human but they have been effective in keeping out bot registration. Now I only get an occasional human spammer registering rather than the flood of automated registrations I got when I first started my forum.

I have also banned some of the most common IP addresses used by automated spammers.

Thanks for the tip and thank you BotScout.