[kiwivc]

I had this problem too and I found a way that is quick and easy to deal with the spambots.

I created a new usergroup with the permissions of the 'Banned Usergroup' and added the following code to the headinclude of my skins:

<if condition="$bbuserinfo['usergroupid'] == XX">
<meta HTTP-EQUIV="REFRESH" content="0; url=http://www.anyaddress.com">
</if>

Just change XX to the usergroup number which you want redirected to the address listed.
Also change http://www.anyaddress.com to whatever address you want them redirected to.

Anyone logging in to your forum who is in this new usergroup will be redirected to the site of your choosing. A user could press the escape key to interfere with the redirection though.

Also I make their advertisement, or part of it, a banned word or make a smilie to interfere with part of their advertising. I had a big problem with wow spam bots and so made a smilie that displays whenever the words wow or WOW are used on my forum.

Some of the spammers use so many proxy IP address it can create a huge amount of work keeping them away. Often I just change their password, delete their posts and get on with my day. The redirection has worked best for me so far.