IP banning

Greets, all.

A friend just installed a webboard system for me at the free webspace host multimania.com. It uses PHP and MySQL (it's a system called AcmlmBoard, which you may or may not have heard of) to run. MultiMania assigns users a dynamic IP address, the last sector of which is the dynamic one. This makes it rather hard to ban people using the AcmlmBoard's IP-ban feature, as everyone appears to have a similar IP.

Does anyone know how I can work around this? The friend setting up the board is stumped, altho he says that if we can somehow ban IPs from accessing the *server* itself (as opposed to accessing the *webboard* which is what the board's own IP ban does) that might work. I personally don't know enough about PHP or MySQL or server technical stuff, myself, to come up with anything.

Please help! ^_^

You can try the .htaccess way if you are allowed to use it. It depends on the server setup, you may place this .htaccess to http://www.multimania.com/webboard/.htaccess so the banned users can still access other parts of your site.
Here is the content of that .htaccess:

<Limit GET POST>
order allow,deny
allow from all
deny from ip.to.ban.here # you can put multiple IPs (a single whitespace-delimited) on the same line
</Limit>

Say your script accepts POST method, you can tighter that to <Limit POST> so those users still have READ access to your board.
You are on your own to figure out how to write such a script to modify the deny from lines.