Some users have recently had their accounts hijacked. It seems that the now defunct EVGA forums might have compromised your password there and seems many are using the same PW here. We would suggest you UPDATE YOUR PASSWORD and TURN ON 2FA for your account here to further secure it. None of the compromised accounts had 2FA turned on.
Once you have enabled 2FA, your account will be updated soon to show a badge, letting other members know that you use 2FA to protect your account. This should be beneficial for everyone that uses FSFT.
Well how are you goign to store your ban list? Mysql, text files? You have to add code to the banned pages to compare the client's IP with your ban list that you'll have to read in and act accordingly.
I know how to do it without the form....but imagine this...you are making a forum system and everytime someone has to IP ban someone they have to go into ftp and edit one of their php files...how user friendly is that?
So anyway, I would guess a database...as long as no queries have to be run from something like phpmyadmin.
Should be pretty easy, assuming you know the basics of connecting to a database with PHP. Just have a table of banned IPs, and add to them whenever the form is called. Make sure you've got strong security on the banform, or you'll be in a world of pain.