If you are worried about the porn spam bot you sould upgrade to the lastest 2.3.0 RC or install the image verfication hack here.
Its differnt because it works with ip ban to, i dont use ip bans unless i ban them from the whole server. IP bans via a the forums are just to much tourble and i end up having to ban many potinal users cause 99% of the people out there do not use a static ip.