Re: Comparing values question.

At 23:15 24.05.2003, Tom Ray [Lists] said: --------------------[snip]-------------------- >I've written a guestbook script and I have IP banning in it. Basically >it checks a flat file with a list of IP address in it and if they match >the users IP they are denied the ability to post. That works all fine >and dandy. But here's my question. > >How do I get it to compare against a block of IPs? So if I was to add >1.1.1.* to the list to block everyone from that IP Block, how do I >compare the 1.1.1.* to like 1.1.1.20 and still have it block? I looked >over things at PHP.net and I'm guessing I'm just looking over something >simple. Anyone have any thoughts or suggestions? --------------------[snip]-------------------- An IP address (dotted notation) is simply a more human-readable notation for a long value. PHP has the ip2long() and long2ip() functions to help with that. Assuming you want to ban the IP range 1.2.3.0 - 1.2.3.255, you could $ban_base = ip2long('1.2.3.0'); $ban_top = ip2long('1.2.3.255'); All you need to do now is to check if a particular IP is within these borders: $ip2check = ip2long($_SERVER['CLIENT_ADDRESS']); if ($ip2check >= $ban_base && $ip2check <= $ban_top) { // banned IP } else { // IP is ok to post } Be aware though that you cannot assume a certain person behind a single IP, because: - there might be more than one PCs having this IP (being a proxy server) - a single PC may change IPs dynamically (Dial-Up, or AOL style) As to my knowledge, IP-based banning is no good thing to do. You may miss the target, or you're banning a whole bunch of people you don't want to ban. Just my 2c worth, -- >O Ernest E. Vogelsinger (\) ICQ #13394035 ^ http://www.vogelsinger.at/